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CQESRIGIIT OEPOSm 



SOIL ALKALI 



WILEY A C; R I C U L T U R A L S li R I K S 

SOIL ALKALI 

ITS ORIGIN, NATURE, AND TREATMENT 



BY 

FRANKLIN STEWART HARRIS, Ph. D. 

DIRECTOR AND AGRONOMIST, UTAH AGRICULTURAL 

EXPERIMENT STATION, AND PROFESSOR OF AGRONOMY 

UTAH AGRICULTURAL COLLEGE 



NEW YORK 

JOHN WILEY & SONS, Inc. 

London: Chapman and Hall, Ltd. 

1920 






COPYRIGHT • 1920 • BY 
FRANKLIN S. HARRIS 



THE PLIMPTON PRESS • NORWOOD • MASS • U • S • A 

©CI.A597386 
SEP -9 i^^^O 



To . 

Dr. JOHN ANDREAS WIDTSOE 

PIONEER-INVESTIGATOR OF ARID AGRICULTURE, TEACHER 
AND FRIEND, THIS BOOK IS AFFECTIONATELY DEDICATED 



PREFACE 

The study of soil alkali is by no means simple, nor have 
all the problems relating to it been solved. The many 
different salts involved, each with its own properties; 
the various types of soils in which these salts occur, all 
with different textures and composition; the complex 
relations between the soluble salts of the soil and the plants 
growing on it; and the several economic factors involved 
in the reclamation of alkali land: these and numerous 
other considerations make the problems connected with 
soil alkaU as difficult to solve as any found in agricultural 
science. 

The excuse for writing a book on a problem that is so 
far from solution is found in the great demand that exists 
for one volume containing the important information 
concerning alkali. At present, the literature of the sub- 
ject is very much scattered and is largely unavailable to 
the average student of soils. 

There are hundreds of millions of acres of land in the 
world that are at present not used for agriculture but which 
might become productive if the alkali could be eliminated. 
The need for more land to supply food for the world's 
increasing population is making a very insistent demand 
that some of these alkali lands be made available. The 
response to this demand will depend on a better under- 
standing of the nature of alkali and methods of reclaiming 
land impregnated with it. This accounts for the new in- 
terest that is being shown in the study of soil alkaU. 



viii PREFACE 

The present volume is intended as a text and reference 
work for students of soils and others interested in arid 
agriculture. It should find wide use by county agricul- 
tural agents and the better trained farmers in regions 
where the alkaU problem is encountered. 

References are given in connection with each chapter. 
The figures in parenthesis in the body of the text indicate 
the number of the reference at the end of the chapter. 
No attempt has been made to cite all the literature, but 
most of the important papers are included. Foreign titles 
have usually been translated into English in order to make 
them clearer to the general reader. Where the original 
article is Ukely to be unavailable an attempt has been 
made to refer to an abstract in some available publication 
such as the Experiment Station Record. 

The author wishes to acknowledge his indebtedness to 
all who have contributed either directly or indirectly to 
the work. He has drawn freely from all available sources, 
but he is particularly indebted to Dr. E. W. Hilgard and 
his associates in California and to the workers in the Bureau 
of Soils, U. S. Department of Agriculture. These two 
sources of information have proved to be veritable "gold 
mines." 

The following who have read part or all of the manu- 
script have given many valuable suggestions: Doctors 
J. E. Greaves, E. G. Peterson, F. L. West, Willard Gardner, 
and G. R. Hill, Jr., and Professors George Stewart, O. W. 
Israelsen, D. W. Pittman, M. D. Thomas, Mrs. B. C. 
Pittman, and Mr. K. B. Sauls. 

The author also wishes to express his appreciation to 
the several assistants and co-workers who have helped in 
his experiments with alkali during a number of years. 
Without the faithful and efficient services of these men the 



• PREFACE ix 

experimental work which led up to this book could not 
have been done. Mr. N. I. Butt deserves special mention 
for his help in reviewing literature and preparing the 
material of this book for publication. 

F. S. Harris 

Logan, Utah 
November i, 1919 



CONTENTS 

CHAPTER PAGE 

I. Introductory 3 

II. Geographical Distribution 6 

North America. Canada. United States. Mexico. South 
America. Africa. Egypt. Europe. Asia. India. Australia. 

III. The Origen of Alkali i6 

Composition of Soil-forming Materials. Salts from Ancient 
Seas. Jurassic Beds, Montana. Arms of the Ocean. Evapora- 
tion of Saline Lakes. Formation of Soluble Carbonates. 
Nitrate Formation. Concentration by Irrigation Water. Rela- 
tion of Origin to Methods of Treatment. 

IV. Nature of Alkali Injury to the Plant 34 

Prevention of Water Absorption. Effects on Germination. 
Effect on Structure of the Plant. Injury at the Surface of the 
Soil. 

V. Toxic Limits of Alkali 42 

Toxicity in Solution. Nutrient Solutions. Alkali Solutions. 
Seed Germination. Seedling Transference into Alkaline Solu- 
tions. Soil Results: in Sand, in Loam Soil. 

VI. Native Vegetation as an Indicator of Alkali 60 

How Plants Indicate the Soil. Alkali-indicating Plants: Well- 
defined Alkali-indicating Plants, AlkaU-indicating Plants not 
Commonly Forming the Major Portion of Alkali-land Vegeta- 
tion. Discussion of Plants: Inkweed or Salt-wort, Tussock 
Grass {Sporobolus air aides), Kern Greasewood or Bushy Sam- 
phire {AUenrolJea occidcntalis) , Dwarf Samphire {Salicornia 
sublerminalis), Greasewood {Sarcobatus vermiculalus) , Alkali- 
heath {Frankcnia grandfolia campenslris), Cressa {Cressa 
cretica truxillensis), Salt-bush or Shadscale {Ahiplex spp.), 
Kochia or White Sage {Kochia vestita), Salt-grass {Distichlis 
spicata), Other Plants. Description of Alkali-indicating Plants. 

xi 



xii CONTENTS 

CHAPTER PAGE 

VII. Chemical Methods of Determining Alkali 8i 

Preparing the Solution: from Moist Soil, from Dry Soil. De- 
termining Total Solids. Carbonate and Bicarbonate Determina- 
tion. Chloride Determination. Sulphate Determination. Nitrate 
Determination. Analytical Process. Determination of Bases: 
Calcium, Magnesium, Sodium. Other Methods of Determining 
Soluble Salts: the Electrical Bridge, Freezing-point Method, 
Biological Method. 

VIII. Chemical Equilibrium and Antagonism , 105 

Solubility of Alkali Salts. Mass Action. Absorption of Salts by 
Soils. Equilibrium in Soil Solution. Antagonism between 
Alkali Salts. 

IX. Relation of Alkali to Physical Conditions in the Soil. ... 119 
Changing Soil Structure. Effect of Colloids. Hardpan. Effect 

on Moisture Movements. Evaporation of Moisture. 

X. Relation of Alkali to Biological Conditions in the Soil . 132 
Relation of Soil Organisms to Fertility. Biological Inactivity 

and Soil Sterility. Concentrations of Alkali which Limit Biolog- 
ical Activities. 

XI. Movement of Soluble Salts through the Soil 141 

Salts in Natural Soils. Salt Movement with Water. Effect of 
Water-table. Movement of Various Salts. Rate of Alkali 
Movement. 

XII. Methods of Reclaimlng Alkali Lands 154 

The Source of Contamination. Reducing Evaporation. Plowing 
under of Surface Alkali. Removing from Surface. Neutralizing 
Sodium Carbonate. Other Chemical Treatments. Cropping 
with Alkali-resistant Crops. Drainage. 

XIII. Practical Drainage 167 

Advantages of Drainage. Determining the Need of Drainage. 
Types of Drains. Cement Tile for Alkali Land: Preliminary 
Survey, Laying out the System, Size of Drains, Construction 
Methods. Outlets and Silt Basins. Cost of Drainage. 

XIV. Crops for Alkali Land 192 

Factors Affecting Resistance. Economic Factors Affecting 
Choice. Tolerance of Alkali by Various Crops; Forage Crops, 



CONTENTS xiii 

CHAPTER PAGE 

XIV {continued) 

Alfalfa, Sweet Clover {Mcliloliis alba and M. officinalis). Other 
Clovers: Vetch {Vicia saliva and V. villosa), Field Peas {Pisum 
sativum), Beans. Grasses: Timothy, Orchard Grass {Daclylis 
glom-erata), Brome Grass {Bromus incrmis), Red Top {Agnostis 
alba), Blueg ass {Poa pralensis), Western Wheat Grass {Agropy- 
ron), Japanese Wheat Grass {Agropyroii J aponicum) , Rye Grass, 
Fescue, Tall Meadow Oat-grass {Arrhcnatherum elatins), Wild 
or Native Grasses, Salt Grass {Distichlis spicala), Bluestem Grass 
{Agropyron Occidenlale), Tussock Grass or Purple Top {Sporo- 
bolus airoides). Alkali Meadow Grass {Puccinellia airoides), 
Prairie Grasses, Modiola {Modiola procumbens). Salt Bushes 
{A triplex spp.). Giant Rye Grass {Elymus condensatus) , Sedges 
and Rushes, Millets, Sorghums, Rape {Brass ica napus and B. 
oleracea). Grain Crops: Wheat, Barley, Oats, Rye, Corn, Rice, 
Emmer, Sunflowers. Root and Vegetable Crops: Sugar-beets, 
Potatoes, Onions, Asparagus, Celery, Radishes, other Vegetables. 
Fiber Crops: Flax, Cotton. Trees and Shrubs: Fruit Trees and 
Shrubs, Date Palms, Grapes, Olives, Other Fruits, Other Trees. 

XV. Alkali Water for Irrigation 224 

Sources of Contamination. Observed Toxic Limits. Compo- 
sition of Typical Alkali Waters. Factors Modifying Toxic Limits 
of Salt. 

XVL Judging Alkali Land 240 

Geology of Region. General Appearance. Native Vegetation. 
The Water-table. Analysis of the Soil. Possibility of Reclama- 
tion. Economic Factors. 

Index 247 



LIST OF ILLUSTRATIONS 

VIC. PAGE 

Wheat Raised on Reclaimed Alkali Land Frontispiece 

1. Salt-bearing Shale Formation 24 

2. Mancos Shale Hill 26 

3. Normal and Plasmolyzed Cells 35 

4. An Orchard Planted on Land that Came from a 

Formation High in Soluble Salts % . . . . 37 

5. The Lower Part of an Orchard being Killed by Alkali 

brought to the Surface by a Rising Water Table. . 39 

6. Experiments to Determine the Toxicity of Various 

Alkali Salts 50 

7. Growth of Wheat with Various Concentrations of 

Different Salts 54 

8. Alkali Crusts at the Surface Preventing the Growth of 

Practically all Vegetation 61 

9. Alkali Land which is Indicated by the Growth of 

Shadscale 62 

10. Greasewood and Shadscale 66 

11. The Border between Greasewood and Salt Grass. ... 68 

12. The Last Plant to Abandon an Alkah Flat 71 

13. Plants Growing at the Top of Sand Dunes 74 

14. Determining Soluble Salts with the Electric Bridge 

in the Field 102 

15. Alkali Coming to the Surface where Seepage Water 

from a Canal Comes to the Surface and Evaporates no 



XV 



xvi ILLUSTRATIONS 

i6. Black Alkali Crust Forming where the Land has been 

Wet 115 

17. Cultivated Land that had to be Abandoned because 

of the Rise of Alkali 143 

18. Alkali Eating away the Fence Posts 147 

19. Typical Hard Pan Found in Arid Soils 156 

20. Field Ready for Laying Tile 16S 

21. Boggy Alkali Land that is Difficult to Drain with 

Short Tile 171 

22. Open Ditch used to Carry away the Drainage 

Water from a Large Area 172 

23. Machine for Making Drains in Heavy Soil without 

the Use of Tile 173 

24. Poorly Made Cement that is being Crumbled by 

Alkali 175 

25. Method of Establishing Grade of Drains 177 

26. Types of Lumber Drains used to Reclaim Boggy 

Alkali Land 180 

27. Wood Drains being used to Drain Boggy Alkali Land 184 

28. Drainage Machine with Digging Wheel above 

the Ground 186 

29. Drainage Machine with Digging Wheel in the Trench 187 

30. Silt Box with Lid. The Silt that Settles in the Box 

can be Spaded Out 189 

31. Alkali Spot in a Grain Field 211 

32. The More Tender Trees are being Killed with Rising 

Alkali, while Alfalfa is Still Unaffected 227 

33. Layer of Alkali Several Feet below the Surface 241 



SOIL ALKALI 



SOIL ALKALI 

CHAPTER I 
INTRODUCTORY 

Whenever the word "alkali " is mentioned there im- 
mediately arises in the minds of some people a vision of 
desolation. They may picture to themselves a barren 
tract of land devoid of vegetation and covered with a 
blanket of white salt mixed with earth; or they may fancy 
that they see worthless wastes of what had been fertile 
helds. They imagine beautiful trees being reduced to 
stumps and fence posts and remnants of farm buildings 
gradually being eaten away by a slowly advancing white 
cover, which will eventually reduce the entire landscape 
to a gray barrenness. Probably each of these pictures 
has a prototype in some local section. Alkali does prevent 
the cultivation of vast areas of land, and it has caused the 
abandonment of many fertile fields; but to give up all 
effort when alkah makes its appearance would be like 
abandoning a farm just because some crop became in- 
fested with a pest. 

The successful pursuit of agriculture calls for the con- 
stant overcoming of difficulties. New problems arise 
each season, but success demands that these be solved. 
The difference between civilization and savagery consists 
largely in meeting difficulties and being masters of nature 
instead of merely victims of circumstance. 

3 



4 INTRODUCTORY 

The welfare of the entire people is dependent on the 
prosperity of agriculture, and in turn agriculture rests on 
the productivity of the soil. Human well-being is therefore 
closely tied up with the land. Whatever affects agricul- 
ture is important not only to the tillers of the soil but to 
all who consume the products of the farm. In order that 
an ample food-supply may be assured at a low price, the 
people generally are interested in having available as large 
a producing area as possible. 

Most of the more desirable lands of the world have been 
settled. This means that an extension of the area of pro- 
duction will often necessitate the use of land that has 
some unfavorable condition. There are in the world vast 
tracts that are not susceptible of cultivation without special 
treatment. In the arid parts of the earth, which comprise 
about one-half of the total land, two great conditions are 
withholding from cultivation millions of acres of land. 
They are drouth and alkali. The successful overcoming 
of drouth and alkali means the addition of countless acres 
to the productive part of the earth. It is with alkali 
and its conquest that the present volume deals. 

It has been estimated that about 13 per cent of the 
irrigated land of the United States contains sufficient 
alkali to be harmful. This means that there are over 
nine million acres of land under present canal systems that 
are affected with alkali. There are many more million 
acres of alkali land in the United States that do not lie 
under irrigation systems. Similar figures might also be 
given for other countries of this continent and for all of 
the other continents. The alkali problem is one of no 
mean importance to farmers, nor to any who are interested 
in the world's food-supply. 

In a strictly chemical sense the word "alkali " refers 



INTRODUCTORY 5 

to a substance having a basic reaction. As applied to the 
soil, however, this restricted meaning does not hold, and 
alkali refers to any soluble salts that make the soil solution 
sufficiently concentrated to injure plants. This includes 
the chlorides, sulphates, carbonates, and nitrates of sodium, 
potassium, and magnesium, and the chloride and nitrate 
of calcium. The sulphate and carbonate of calcium are 
not sufficiently soluble to be injurious to crops. Most of 
the alkalies are in reality neutral salts. It may be some- 
what unfortunate to use for general substances a word that 
also has a restricted technical meaning, but the word 
has become so well established in agricultural literature 
that it would now be very difficult to change it. 

Aside from their practical importance, the soluble salts 
of the soil are of great scientific interest. They offer 
fruitful fields for investigation to the geologist, the chemist, 
t^e plant physiologist, the bacteriologist, the mycologist, 
the agronomist, and the engineer. The complexity of 
the soil makes the problems connected with alkali very 
difficult to solve. There are so many interacting factors 
that no simple statement of the problem can be made 
and no simple solution arrived at. A complete under- 
standing of the problem will call for careful researches by 
investigators in different branches of science and a careful 
coordination of the findings. The importance of the 
subject justifies giving it the' most careful consideration. 



CHAPTER II 
GEOGRAPHICAL DISTRIBUTION 

Soils containing injurious quantities of alkali are found 
on every continent. These soils, however, do not occur 
in all parts of the continents, the distribution being con- 
fined to areas where conditions favorable to their formation 
prevail. The most important of these conditions is aridity. 
Another important factor is the nature of the rock from 
which the soils were formed. Because these conditions 
are local, alkaH soils are likely to be found over large areas, 
but all the soils of these areas are not necessarily highly 
charged with soluble salts. Part of the soils in a region 
having a climate favorable to alkali formation may be 
derived from rocks that are low in soluble salts and may 
have been so deposited that they have good natural drain- 
age. Soils of this kind do not contain alkali even though 
most of the soils of the region are impregnated. Likewise, 
soils high in soluble salts may be found over limited areas 
in regions where most of the soils are free. This condition 
is sometimes found in climates that are not entirely arid, 
or where a soil having poor drainage was derived from 
rock that was high in soluble salts. Thus, the alkali 
problem has local as well as general aspects. A general 
alkali condition may prevail over an extensive region, 
the smaller areas of which may be exceedingly variable. 

North America. — More than half of the North- Ameri- 
can continent is arid or semi-arid. Throughout this vast 
area alkali soils are found. There are many large tracts 

6 



CANADA 7 

in which the soluble salt content of the soil is not at present 
sufficient to interfere with crop growth, but there is suffi- 
cient of the salts present if concentrated by unwise methods 
of irrigation, by drouth, or by other means to bring the 
soil to the danger point, especially should drainage be poor. 

The looth meridian may be taken roughly as the line 
separating the humid from the arid part of the continent. 
This Hne is not absolute; it varies somewhat with latitude, 
altitude, and several other factors. There are a number 
of places west of this line where the rainfall is high. This 
is i)articularly true along the northwest coast and along 
some of the mountain ranges. 

Canada. — In western Canada, especially in the prov- 
inces of Saskatchewan, Alberta, and British Columbia, 
there are several rather large tracts where the soluble- 
salt content of the soil is sufficiently high to render crop 
production difficult. In southeastern Alberta the soil of 
one of these regions originated from the glaciation of shale 
that was high in soluble salts, particularly the sulphates. 
Therefore, sulphates are the predominating salt of the 
region. The soil is heavy^ and impervious; consequently, 
there has been very little movement of salts from its original 
place in the soils. 

Under irrigation these salts may be either leached down- 
ward or brought to the surface. When appearing as a 
white inflorescence they are very conspicuous and would 
lead the casual observer to believe the condition to be 
much worse than it really is. A large quantity of gypsum 
is present in these soils and, when dissolved and brought 
to the surface, it, together with sodium sulphate, forms 
a conspicuous white soil covering. Fortunately, the 
percentage of the more harmful chlorides and carbonates 
is verv low. 



8 GEOGRAPHICAL DISTRII^UTION 

The composition of an alkali soil in Alberta as determined 
by Shutt (i6) is given in the following table. 



Table I. Soluble Salts in Alkali Soil of Alberta, Canada 
(Per Cent) 



Depth 
(feet) 


Growth 


Na2S04 


MgSOi 


CaS04 


Total Soluble- 
saline Content 


0.0-0.5 












0.5-1-5 


Good 


.178 


.087 


.163 


.440 


I- 5-30 




.877 


■132 


■447 


1572 


3 0-5.0 




•973 


.563 


2.926 


4.640 


30-S.O 


Poor 


.123 






.180 






.701 


.247 


.491 


1.480 






.719 


•309 


.588 


1.680 






•799 


.062 


.192 


1.060 


30-5. 


No 


1. 741 


.goo 


.648 


3.260 






1 .001 


323 


•364 


1.700 






.701 


.222 


.220 


1. 164 






•579 


.084 


.192 


.900 



United States. — In sixteen or seventeen of the western 
states of the Union, alkali is found to be one of the chief 
agricultural problems. The problem is much more acute 
in some regions than others. The San Joaquin, Sacra- 
mento, and Imperial Valleys of California; the Great 
Basin, comprising a large part of Utah and Nevada; 
the Colorado River drainage basin, comprising parts of 
Wyoming, Utah, Colorado, Arizona, and California; 
the Rio Grande River drainage area, including parts of 
New Mexico and Texas; parts of the Columbia River 
drainage basin ; and rather extensive sections in the Great 
Plains east of the Rocky Mountains include the most 
important parts of the United States affected with alkali. 
In practically all the western states certain areas affected 
by alkali have been described in publications of the state 



MEXICO 



experiment stations or in the United States Bureau of 
Soils. (See Table II.) These publications show that the 
composition of the alkali salts as well as the methods of 
reclamation vary greatly. 

Table II. Composition of Alkali from Different Parts of 

THE United States Expressed in Percentage of 

Different Salts 





Percentage of Different Salts in the Alkali 


Salts 


Colorado! 


California- 


VVashing- 
toii' 


Montana' 


Arizona^- 




Crust 


Surface, 
10 in. 


Crust 


0-72 in. 


KCl 

K2SO4 

K2CO3 

NaoS04 

NaN03 

NasCOs 

NaCl 

Na3HP04 

MgS04 

MgCl2 

CaCl2 

NaHCOs 

CaS04 

Ca(HC03)2. . . . 
Mg(HC03)2. . . 

(NH4)2C03.... 


1 .64 

33-07 
6.61 

12.71 
17.29 

21.48 


3-95 

25^28. 
19-78 
32-58 
14-75 
2.25 

1. 41 


5.61 
9 73 

13-86 

36.72 

1.87 

16.48 

15-73 


I .60 

85-57 

0-55 
8.90 

0.67 
2.71 


21.41 
35-12 
■7^28 

4.06 

22.06 
10.07 


4.00 

81.15 

7.71 
0.25 
0.28 
6.61 


22.10 

13-77 

6!88 
3-98 

21.02 
32.25 



Mexico. — The greater part of the high plateau of 
Mexico has an arid climate. This, like all similar regions, 
has had but comparatively little of the soluble salts 
contained in the country rock removed. In this section 
there are many large valleys having no outlets. During 

' Colorado E.xp. Sta., Bui. 155, p. 10. 
^ Hilgard "Soils," p. 442. 
' U. S. D. A. Bur. Soils, Bui. 35, p. 79. 
^ U. S. D. A. Bur. Soils, Bui. 35, p. 103. 
6 U. S. D. A. Bur. Soils, Bui. 35, p. 109. 



10 GEOGRAPHICAL DISTRIBUTION 

the rainy season the lower parts of these valleys are flooded 
by the waters of swollen streams; during the dry season 
this water is practically all evaporated, leaving its soluble 
material behind. This results in great level bodies of 
land charged in varying degrees with soluble salts. The 
composition of these saline deposits depends on the com- 
position of the country rock through which the streams 
flow. Very little work up to the present time has been 
done to reclaim the alkah soils of Mexico. 

South America. — No important published material is 
available on the alkah condition of the soils of South 
America. It is known, however, that the arid sections of 
that continent do not differ essentially from those of other 
arid sections of the world. Practically the entire western 
part of the continent is arid and throughout this section 
areas subject to alkah troubles are found. It includes 
most of the Pacific slope west of the Andes and the greater 
part of the western plains of Brazil and Argentina east of 
these mountains. 

The deposits of sodium nitrate in Chile are a conspicuous 
example of the retention of soluble salts that would be 
leached out in a humid chmate. 

Africa. — The distribution of alkali soils in Africa is not 
the same as in North and South America. It is found 
over practically the entire northern portion of the con- 
tinent and also in the southwestern part. The central, 
and particularly the west-central, portion is practically 
free. Throughout the Union of South Africa up into 
Rhodesia alkali soils are found but have not received as 
much attention as some of the sections of North Africa, 
particularly in Egypt. The soils of the Sahara as well as 
many of those of Algeria, Morocco, and Tunis are so 
contaminated with soluble salts that it was necessary for 



EGYPT 1 1 

the agriculture of these countries to be adjusted to this 
condition. It is probable that the alkah problem is being 
given more consideration in Egypt than elsewhere. 

Egjrpt.- — The greater part of Egypt is a barren desert, 
being one of the most desolate parts of the earth. The an- 
nual precipitation at Alexandria averages 8.26 inches; 
at Port Said, 3.49 inches; and at Cairo it is only 1.06 
inches, which is not enough to support vegetation of any 
kind. The country is traversed from south to north by the 
Nile River along which is a narrow, highly cultivated, and 
thickly populated strip of river-formed land. In the 
southern part of the country the river flows through sand- 
stone and occupies a shallow valley, but farther north a 
deep gorge is cut down from the surrounding limestone 
plateau. On both sides of the river are alluvial plains 
composed of fine silt which for the most part has been 
carried by the Nile from the disintegrated volcanic material 
of the Abyssinian highlands. Thus the soil of the lower 
Nile Valley bears no relation to the country rock of the 
immediate vicinity. 

In the delta portion of the valley, the land is very flat 
and there is but little opportunity for drainage. Much 
land that was cultivated anciently has since been abandoned 
on account of the accumulation of alkah. The area thus 
abandoned has been estimated to be more than one and 
a half million acres. Most of this land is on the fringe 
that borders the sea and is influenced by sea water. The 
higher lands are practically free from alkah. 

Formerly all the land was watered by the basin system 
of irrigation. With this method, the land is flooded to a 
depth of from three to five feet at the season when the Nile 
is high. After standingat this depth for al)out six weeks 
and allowing the sediment to settle, the water is drained 



12 



GEOGRAPHICAL DISTRIBUTION 



back into the Nile, and the crops are planted in the mud 
without plowing. By this system only one crop is grown 
each year, but the accumulation of alkali is prevented by 
washing part of it to lower depths in the soil, by depositing 
a fresh layer of salt-free silt on the surface, and by carrying 
away with the water that is drained off any soluble material 
that may have accumulated on the surface at the time of 
flooding. 

In order to raise more than one crop a year and thereby 
get greater profit from the land, the basin system of irri- 
gation is being largely supplanted by the perennial system, 
by means of which water is applied throughout the year. 
This brings about almost continuous evaporation from the 
surface and a consequent accumulation of soluble salts. 
Of the 6,250,000 acres of irrigable land in Egypt, only 
about 1,730,000 acres are irrigated by the old system of 
basin irrigation. This means that the alkali problem 
will continue to be more acute in Egypt until suitable means 
of coping with it are worked out. Already some rather 
ingenious methods (23, 25) of drainage are in operation. 

The following analysis reported by Means (14) of an 
alkali soil from Kom-el-Akhdar is typical of the alkali 
land of lower Egypt: 

Table III. Chemical Analysis of Alkali Soil from Kom-el- 
Akhdar, Egypt (Surface foot) 



Ions 



Per cent 



Conventional Combinations 



Percent 



Calcium (Ca) 

Magnesium (Mg) 

Sodium (Na) 

Potassium (K) 

Sulphuric Acid (SO4) .... 

Chlorine (CI) 

Bicarbonate Acid (HCO3) 



307 

2.00 
28,83 

1 .90 
24.56 
38.62 

1 .02 



Calcium Sulphate (CaSO^). . . . 
Magnesium Sulphate (MgS04) 
Potassium Chloride (KCl) .... 

Sodium Chloride (NaCl) 

Sodium Bicarbonate (NaHCOs) 

Sodium Sulphate (Na2S04) .... 

Per cent Soluble 



10.43 
9.90 
3.62 

60.88 
1. 41 

1376 



8.2 



INDIA 13 

Europe. — Of all the continents, Europe is the most 
free from alkali, although it has several alkali sections. 
Probably the most conspicuous of these is found in Hun- 
gary. The "Szik " lands of the plains contain some soluble 
salts and lower down in the valley of the Theiss genuine 
alkali lands are found with a high content of both white 
and black alkali. From these lands carbonate of soda 
has long been obtained commercially. In the lower 
valley of the Po in Italy (2) and in many other sections 
of Europe bordering the Mediterranean local alkali areas 
are found. 

Asia. — The main alkali regions of Asia are found in 
the central and southwestern portions of the continent. 
Arabia, Mesopotamia, Persia, Afghanistan, Baluchistan, 
Turkestan, and Northern India are all more or less affected 
with alkali salts. In some of these countries agriculture 
has continued in spite of the excess of soluble salts because 
special methods have been devised as a result of experience 
extending back to prehistoric times. 

Modern investigations of alkali have been more complete 
in India than in other parts of Asia; consequently, more 
attention will be given to that country in the present 
discussion. 

India. — The alkali, or reh, lands of India were first 
investigated by the "Reh Commission " about 1876. 
This commission was appointed to discover the cause of 
deterioration of some of the lands that had previously been 
fertile. Since that time the various experiment stations 
in India have made more extensive investigations. They 
have shown that "usar" lands (12) exist largely not only 
in the northwestern provinces and Oudh, but also in the 
Punjab, especially on lands bordering the Chenab River, 
likewise to a slight extent in the Bombay Presidency. 



14 GEOGRAPHICAL DISTRIBUTION 

The Reh Commission brought out the fact that under 
the ancient systems of agriculture in India there was very 
httle increase in the amount of soluble salts at the surface, 
but with the construction of large modern canals and the 
appHcation of unnecessarily large quantities of irrigation 
water the increase in alkali was very rapid. 

Leather (12) has pointed out that not all the lands called 
by the natives "usar " owe their infertility to alkali. Some 
simply have very hard clay soils which are difhcult to 
bring into a good state of tilth. The true "reh" lands, 
however, are like the alkah lands of other parts of the 
world. 

Australia. — The greater part of Australia may be con- 
sidered as arid although the rainfall of the eastern part of 
the continent is high. During the last generation large 
irrigation works have been constructed and vast tracts of 
land containing a rather high content of soluble salts have 
been brought under cultivation. In such sections alkali 
is one of the serious problems. Alkah conditions in Aus- 
tralia are somewhat similar to those of the western part of 
the United States. 



REFERENCES 

1. Ames, J. W. Some Alkali Soils in Ohio. Ohio Sta. Mo. Bill, i (1916), 

No. 7, pp. 209-210. 

2. Atti, R. a Saline Soil of the Lower Valley of the Po (Italy). Accad. 

Econ. Agr. Firenze, 5, Ser. 3 (1906), No. i, pp. 59-64. (Abs. E. S. 
• R. 18, p. 215.) 

3. Bancroft, R. L. The Alkali Soils of Iowa. Iowa Sta. Bui. 177 

(1918), pp. 185, 208. 

4. BuRD, J. S. Alkali Conditions in the Payette Valley. Idaho Sta. 

Bui. 51 (1905), pp. 1-20. 

5. Clarke, F. W. The Data of Geochemistry. U. S. Geol. Survey, 

Bui. 616 (1916), pp. 143-167 and 206-247. 

6. Deakin, Alfred. Irrigated India, 322 pp. (London, 1893.) 



REFERENCES 15 

7. DiMO, N. A. Innuciuc of Irrigation and of Increased Natural IIu- 

midily on tlic Process of Salt I-ormation and of tlie 'rrans[)ortation 
of Salts in the Soils and Subsoils of Ciolodnoi (Ilunj^ary) Stcjipe, 
Smarkand Province. Kuss. Jour. iCxj). Landw. 15 (1914), No. 2, 
PP- 336-338. (Abs. K. S. R. 34, p. 16.) 

8. Hebert, a. Alkali Soils from the Knee of the Niger River. Hul. 

Soc. Chim., France, 4, Ser. 9 (191 1), Nos. 16, 17, pp. 842-843. 

9. HiLGARD, E. W. Soils, pp. 423-424. (New York, 1906.) 

10. Hill, E. G. The Analysis of Rch, the Alkali Salts in Indian Usar 

Land. Proc. Chem. Soc, London, 19 (1903), No. 262, pp. 58-61. 
(Abs. E. S. R. 14, p. 1056.) 

11. Ke.arney, T. H., and Means, T. H. Crops Used in the Reclamation of 

Alkali Lands in Egypt. U. S. D. A. Yearbook (1902), pp. 573-588. 

12. Leather, J. VV. Investigation of Usar Land in the United Provinces, 

Allahabad, India. Govt., 1914, pp. 88. (E. S. R. ^:i, p. 419.) 

13. Mann, H. H., and Tamhaxe, \^ .\. The Salt Lands of the Nira Valley 

(India). Dept. of Agr., Bombay, Bui. 39, 35 pp. 

14. Means, T. H. Reclamation of Alkali Lands in Egypt. U. S. D. A. 

Bur. of Soils, Bui. 21 (1903), 48 pp. 

15. MacOwan, p. Black Land in Relation to Irrigation and Drainage, 

.Agr. Jour. Cape Good Hope, 23 (1903), No. 5, pp. 573-581. 

16. Shutt, E. T. and Smith, E. A. The Alkali Content of Soils as 

Related to Crop Growth. Trans. Roy. Soc. Can. Ser. 3 (1918), 
Vol. 12, pp. 83-97. 

17. SiGMOND, A. VON. On the Types of "Szik" Soils of the Hungarian 

.■\lfold. Eoldtani Kozlony, 36 (1906), No. 10-12, pp. 439-454. 
(.Abs. E. S. R. 19, p. 1117.) 

18. Snow. F. J., Hilgard. E. W.,and Shaw, G. W. Lands of the Colorado 

Delta in the Salton Basin. Cal. Sta. Bui. 140 (1902), pp. 51. 

19. Stevenson, W. H., and Brown, P. E. Improving Iowa's Peat and 

Alkali Soils. Iowa Sta. Bui. 157 (1915), pp. 45-79. 

20. Traphagen, F. W. The Alkali Soils of Montana. Mont. Sta. Bui. 18 

(1898). pp. 50. 

21. Tulaikov, N. Soils of the Kirghiz Steppe. Russ. Jour. Exp. Landw. 

9 (1908), pp. 628-630. (Abs. E. S. R. 22, p. 617.) 

22. VissoTSKi, G. The Soil Zones of European Russia in Connection 

with the Salt Content of the Subsoils and with the Character of the 
Forest Vegetation. Pochvovedenie (Pedologie), i (1899), pp. 
19-26. (Abs. E. S. R. 12, p. 925.) 

23. WiLLCOCKS, W. Egy[)tian Irrigation, 485 pp. (London and New 

York, 1899.) 

24. WiLLCOCKS, \V. The Irrigation of Mesopotamia. (London and New 

York, 191 1.) 

25. WiLLCOCKS, W. The Nile in 1904, 225 pp. (London, 1904.) 



CHAPTER III 
THE ORIGIN OF ALKALI 

The presence of alkali incrustations over the surface of 
the soil was observed long before scientists were able to 
account for the origin of these salts. This led to quite 
a number of theories regarding the source of the alkali. 
Several of the early theories have been found untenable 
in the light of later investigation. Many of the formerly 
obscure facts are now definitely known and there is a much 
clearer idea of the source of the soluble salts of the soil; 
but even today considerable difference of opinion exists 
regarding the origin of some of these salts. More data 
must be gathered before it will be possible to state definitely 
why certain deposits of alkali occupy their present position 
and maintain their present composition. It is definitely 
known that there are a number of distinct conditions 
promoting the accumulations of alkali in various sections. 



Table IV. Average Composition of Igneous Rocks, Shale, 
AND Sandstone (Per Cent) 



Quartz 

Feldspar 

Hornblende and pyroxene. 

Mica 

Clay 

Limonite 

Carbonates 

Other minerals 



Igneous Rocks 



12. 

59 
i6 

3 



Shale 



22.3 
30.0 



Sandstone 



66.8 
ii-S 

6^6 

1.8 

li.i 

2.2 



16 



COMPOSITION OF SOIL-FORMING MATERIALS 17 



Composition of Soil-forming Materials. There seems 
to be no doubt that the soluble salts of the soils have come 
from the same materials as the soils. The exact chemical 
reactions that have brought about these changes and the 
methods of concentrating the soluble constituents are, 
however, not so well known. The materials composing 
the soil have been derived largely from the rocks and 
minerals which constitute the crust of the earth, together 
with a greater or lesser quantity of organic matter coming 
from the dead bod ies of plants. 

Table V. Average Composition of the Lithosphere 





Ipneous 
(95 per cent) 


Shale 
(4 per cent) 


Sandstone 

(0.75 per 

cent) 


Limestone 

(0.2s per 

cent) 


Weighted 
Average 


SiOs 

AI2O3 

FeoOa 

FeO 

MgO 

CaO 

NajO 

K2O 

H2O 

TiOz 

ZrOa 

CO2 

P2O5 

S 

SO3 


59 
14 

2 

3 
3 
4 
3 
2 
I 


83 
98 
65 
46 
81 
84 
36 
99 
89 
78 
02 
48 

29 
II 


58.10 

IS 40 

4.02 

2^45 
2.44 

3-II 
1.30 

3^24 

5.00 

.65 

2.63 
•17 

■"■.64 

•OS 

"'^So 


78.33 
4-77 
1.07 

•30 
1. 16 
5-50 

•45 
131 
1.63 

•25 

5^03 
.c8 

.07 
•05 


5^19 
.81 

•54 

"7'89 
42.57 
•OS 
■33 
•77 
.06 

41 54 
.04 
•09 
•OS 
.02 

•05 


59 

14 

2 

3 
3 
4 
3 

2 
2 


77 
89 
69 

39 
74 
86 

25 
98 
02 

77 
02 
70 
28 
10 

03 
06 
09 

09 
04 
09 
025 

OS 

025 

01 


CI 

F 

BaO 

SrO 

MnO 

NiO 

CrsOs 

V2O3 

LiiO 

C 




06 
10 
10 
04 
10 
025 

05 

02s 

01 










100.000 


100.00 


100.00 


100.00 


100.000 



18 



THE ORIGIN OF ALKALI 



Compilations made by Clarke (6) show the earth's 
crust to be made up largely of the important minerals 
shown in Table IV (page i6). 

On the basis of the composition and relative amount of 
the different rocks he computes the average composition 
of the earth's crust as shown in Table V (page 17), 

Clarke (6) gives the composition of the ocean waters 
as follows: 

Table VI. Composition of Ocean Water 



Salts 


Per cent 


Elements 


Per cent 


Sodium Chloride (NaCl) 


77.76 


Oxygen 


85 79 


Magnesium Chloride (MgCl.;) . . . 


ID 


88 


Hydrogen. . . . 


10 


67 


Magnesium Sulphate (MgS04). . 


4 


74 


Chlorine 


2 


07 


Calcium Sulphate (CaS04) 


3 


60 


Sodium 


I 


14 


Potassium Sulphate (K2SO4) • • . . 


2 


46 


Magnesium . . . 




14 


Magnesium Bromide (MgEr^) . . . 




22 


Calcium 




0^ 


Calcium Carbonate (CaCOs) ... 




^4 


Potassium. . . . 




04 






Sulphur 




oq 






Bromine 




008 






Carbon 




002 




100 . 00 




100.00 



He reports a maximum saUnity of 37.37 grams of salts 
to a kilogram of water, or 3.737 per cent with an average 
of about 3.5 per cent. 

These figures give a general idea of the materials from 
which soils are made and the substances which have been 
leached from them. 

In order to determine soluble matter that might be 
washed from rocks and minerals of various kinds, Whitney 
and Means (23) compiled the material contained in Table 
VII from the writings of G. P. Merrill. 

This table gives an idea of the material that is usually 
washed from rocks and minerals of different kinds in the 



COMPOSITION OF SOIL-FORMING MATERIALS 19 

Taiu.k VII. y\M<)UNT OF Soluble Matter Removed in the 
Decomposition of Rocks and the Formation of Soils 







Rock Removed by Solu- 






tion FROM Each Acre- 






foot OF Soil Formed 


Kind of Rock 


Locality 






Per cent 


Tons 


(iranito 


District of Colunihia 


i,^ 


26r 


(Jiieiss 


Virj^inia 


45 


1,431 


Syenite 


Arkansas 


5" 


2,227 


]*henolite 


Bohemia 


ID 


1 95 


Diabase 


Massachusetts 


15 


309 


Diabase 


Venezuela 


40 


1,166 


Basalt 


Bohemia 


44 


1,376 


Basalt 


France 


60 


2,625 


Diorite 


Virginia 


38 


1,072 


Soapstone 


Maryland 


52 


1,89s 


Soapstone 


Virginia 


78 


6,204 


Limestone 


Arkansas 


98 


85,760 



formation of soils. Dissolved material may be washed 
to the sea or into lakes, or it may simply be transferred to 
lower lying soil and there often concentrated so highly 
that it becomes injurious to plant growth. Some of these 
dissolved materials, such as limestone, are not sufficiently 
soluble to be troublesome even in the highest possible 
concentrations. 



Table MIL 



Percentage of Alkalies in Various Soil- 
forming Minerals 



Feldspars 


Per cent 
of Alkalies 


Micas 


Per cent 
of Alkalies 


Orthoclase 


17 
17 
12 

Q 

8 

4 
35 

2 


Muscovite 

Biotite 

Phlogopite 

Nepheline 

Leucite 


12 


Microline 

Albite 

Olioclase 

Andesite. . . 


10 

9 

24 

21 . =; 


Labradonte 


Sodalite 

Haiiyne 


26 


Bytownite 


17 


Anorthite 









20 THE ORIGIN OF ALKALI 

The same authors (23) give a list of alkaH-bearing min- 
erals occurring in primary rocks as the ultimate source 
of soil alkah. 

"Some of these alkali-bearing minerals are very generally 
present in the primary rocks from which the soils have all 
ultimately been derived, but they are of course usually 
mixed with other minerals, so that the total percentage of 
alkaHes in the rock is not so great as would appear from 
these minerals." 

As to the method of separating these soluble substances 
and transferring them to the surface, Cameron suggested 
a hypothesis which is quoted by Dorsey (7) as follows: 

"The major part of the complex crystalline masses or 
of rocks forming the earth's crust contain chlorine and 
sulphur. F. W. Clarke gives as an average 0.07 per cent 
chlorine and 0.108 per cent sulphur. As a result of the 
hydrolyzing action of water and other decomposing agencies 
probably all the chlorine and very much of the sulphur 
is converted into hydrochloric acid and sulphuric acid, 
which in turn form the corresponding salts of the alkalies 
and alkaHne earths. The aggregate amount which is 
thus being constantly formed in the subsoils and under- 
lying strata of any one area must be very large. As 
evaporation proceeds at or in the surface soil, there Is a 
rise of the water in the underlying layers through the 
capillary spaces toward the surface, bringing with it the 
hydrochloric and sulphuric acids or their salts. 

"The sulphuric acid moves up more slowly than does 
the hydrochloric acid; partly, perhaps, because the rock 
masses and the soils have a greater absorbing action on 
sulphuric than on hydrochloric acid, tending to withdraw 
it from solution; partly, perhaps, because reducing con- 
ditions may exist on some layers tending to the formation 



COMPOSITION OF SOIL FORMING MATERIALS 21 

of metallic sulphides; and, partly, undoubtedly, to the 
formation of the slightly soluble calcium sulphate. This 
last, however, is gradually brought toward the surface, 
and is often found in enormous masses at moderate depths 
in the soils of arid regions. Undoubtedly the calcium 
carbonate so generally found in large masses at moderate 
depths in the soil of arid regions originates in a similar 
manner. 

"Hydrochloric acid is transported through soils and 
most absorbing media with comparative ease. Moreover 
the chlorides of the alkalies and alkaline earths are readily 
soluble. Chlorides should be expected, therefore, to 
accumulate in preponderant masses at the surface, which 
under arid and semi-arid conditions they generally do. 

"The preponderance of sodium chloride above other 
chlorides is readily expHcable. It is well known that when 
solutions of chlorides are poured through columns of soil 
or similar substances, offering a large surface of contact 
to the solution, there is a well-marked selective absorption, 
the soil tending to withdraw the base from the solution 
to a decidedly greater extent than the acid, with the result 
that the leaching generally contains free acid. So far as 
the experience we have goes, it would seem that, in general, 
soils absorb potassium most readily, then magnesium, 
calcium, and sodium in the order named. Supposing the 
hydrochloric acid when found in the lower layers to be 
neutrahzed with a mixture of these bases, as it rises in the 
capillary movement, there is always a tendency, owing to 
the selective absorption of the soil, toward a lagging 
behind of the potassium, a lesser lagging of the magnesium 
and calcium (these bases probably tending also to form 
the much less soluble sulphates and carbonates) and a 
much less lagging of the sodium. In consequence, sodium 



22 THE ORIGIN OF ALKALI 

is the predominating base in the readily soluble salts at 
the surface." 

This hypothesis does not explain the method of accumu- 
lation of alkali at certain places in the soil; it merely 
attempts to show why certain salts are present at the sur- 
face in larger quantities than others. 

Salts from Ancient Seas. — The observation that alkali 
is found in large quantities in one section, whereas it 
may be almost entirely lacking in another section of sim- 
ilar climatic conditions early led to an attempt to trace 
the salt to the rock from which the soil was formed. 
Traphagen (21), at the suggestion of W. H. Weed of the 
U. S. Geological Survey, made a comparison of the composi- 
tion of the alkali near BilKngs, Montana, with the soluble 
salts in the Fort Benton shales from which the soils were 
in part derived. As a result of this study he was led to 
the conclusion that in this case the soluble salts in the soil 
resulted from a transference of the salts to the soil while 
the shale was being disintegrated. This theory was 
afterward supported by the work of Whitney and Means 
(23) in the same region. Cameron (4) also mentions shale 
and similar deposits as a source of alkalies. 

It seems, however, to have been left for Stewart, Peter- 
son, and Greaves (17, 16, 19, 18) to explain clearly the 
intimate relation existing between present alkali accu- 
mulations and the presence of large quantities of alkali 
salts in country rocks from which these soils were formed. 
They made extensive examinations of the geological 
formations in Utah, Colorado, Arizona, Wyoming, Idaho, 
and Nevada, and analyzed the soil-forming country rock 
of these areas. 

These examinations and analyses revealed the fact that 
in these sections wherever alkali is present in very large 



JURASSIC BEDS 2.^ 

quantities it apparently originated from materials de- 
posited from concentrated solutions in some ancient sea. 
The deposits in the areas studied were made during Cre- 
taceous and Tertiary times which seemed to have been 
influenced by arid cHmatic conditions. This area in- 
cluding the eastern part of Utah, the western half of 
Colorado, and the southwestern part of Wyoming was 
covered with water during upper Cretaceous times leaving 
the Uintah antichne as an island. 

A description of the method of formation of these shales 
and sandstones that are so high in soluble salts is given 
as follows (17) : 

" Jurassic Beds. The Jurassic beds contain highly 
colored red, yellow, gray, green, or blue shale and sand- 
stone ranging from line grain to coarse grits. In the 
upper members of the deposit are often found thin lenses 
of limestone and an accumulation of gypsum. The ac- 
cumulation and position of the gypsum beds would seem 
to indicate that they had resulted from precipitation from 
the water of isolated brackish lakes. 

"At the end of Jurassic times the inland sea, in which 
the Jurassic deposit accumulated, disappeared and the 
area was subjected to erosion. This probably took place 
during lower Cretaceous times. Later the section was 
again covered with an inland sea and deposits were laid 
down unconformably on top of the Jurassic. 

''These belong to the Dakota beds, the lower part of 
which were composed of conglomeifates and coarse sand- 
stones, above which are carbonaceous shales and some low- 
grade coal, overlain by more sandstone and highly colored 
shales. Above the shale are found thick beds of light- 
colored sandstone, shales, and dark-brown sandstones. 

"At about the end of the Dakota period there seems to 



24 THE ORIGIN OF ALKALI 

have been some shifting and readjusting of the land as the 
Dakota beds are found to be quite thick in the northern 
section where the Mancos are thin; while in the southern 
section the Mancos are found to be exceedingly thick in 
places where the Dakota is comparatively thin. 

"Where they are not capped with the sandstone the 
beds do not form abrupt ledges, but weather off into rather 
rounded symmetrical clay hills — at least they appear 










Fig. I. — Salt-bearing Shale Formatiun. This Type of Soil- ' 
FORMING Material is a Common Source of Alkali. 

to be clay hills. This disintegration of the shales gives 
rise to a very sticky, plastic clay which forms numerous 
cracks when dry, but becomes a continuous coat of plastic 
clay when wet. The material is so close grained that 
when rain falls upon it, it seals up all the pores and cracks 
so that water does not seem to penetrate it. These hills 
are very sparsely covered with vegetation and it is not an 
unusual thing to see an area of more than an acre which 
does not contain a single plant. 

"On these rounded clay hills one seldom has to dig more 
than a foot before the shale is found in place. However, 
the material covered is not uniform, especially on top of the 
clay knolls. The usual condition is that on the surface 
is from one to two inches of earthy clay, under which is 



MONTANA 25 

from one to six inches of what appears to be a gray ashy 
material. On close examination this proxies to be crystals 
of salt together with flocculent clay. Immediately under 
this is found the shale in place. Samples of the clay and 
gray ashy material, and the shale in place were taken 
separately, and the analyses show the nitrate contents of 
each. 

"The dark-colored shales show numerous crystals of 
g>psum in the cracks and bedding planes. Where the 
shale is dry and considerably weathered the gypsum 
appears Hke white flour. In the seams of the shale, but 
a foot or more under the surface in the same place, the 
crystals are still firm and solid. 

"At Emery, Utah, the gypsum crystals were not only 
taken out of the bedding plane of the thick layers, but 
numerous cross fractures WTre found which were also 
filled with gypsum crystals. Many of these cross fractures 
were as much as a half inch thick and pieces of gypsum 
this thickness and a foot long were removed from the 
shales. 

"Montana. — Overlying the Mancos is the Montana 
Mesa Verde formations which are essentially sandstones, 
shales, and grits, light gray to dark brown in color. Car- 
bonaceous shales with thick beds of workable coal occur 
near their base, while sandstone occurs in the upper part. 
' Transition marked by increase of sandstone upward and 
appearance of brackish and fresh water arise instead of 
marine conditions.' 

"The upper layers of sandstone are often found in thick 
lenses and in many places contain high percentages of 
gypsum. The vegetation accumulated in these shallow 
seas resulted in the formation of coal. The sea seems to 
have increased sufficiently after the formation of the coal 



26 THE ORIGIN OF ALKALI 

so the area was covered with thick la}'crs of sand and 
shale, but the sea does not seem to have continued without 
interruption. Arid conditions seem to have again pre- 
vailed and the sea was reduced so that isolated portions 
became brackish and from these isolated waters gypsum 
and other salts were precipitated. 

**At the end of the Montana series the sea seems to 
have again entirely disappeared and the area was subject 
to erosion. 

"In the beginning of Tertiary times the section was 






"!S^ 






/ 










,i 



Fig. 2. — Mancos Shale Hill. Soil from this Formation 
IS High in Alkali. 

again covered with inland seas over much the same area 
as that occupied by the upper Cretaceous. The lower 
portion of these Tertiary deposits consisted of yellow and 
reddish-yellow sandy clays with regularly bedded sand- 
stones, with some conglomerates near the base, over which 
were deposited thin beds of light-colored sandstones asso- 
ciated over much of the area, especially in Utah, with 
rhyolitic ash beds and fresh-water deposits. In some 
places the ashes show distinct stratification as though they 



ARMS OF THE OCEAN 27 

had fallen into the inland sea and had been worked over 
by the water. 

"The upper part of the Tertiary is composed of shaly 
sandstone and arenaceous shale, and in some sections 
thick beds of subbituminous coals. The shale and much 
of the sandstone are gypsiferous and in many places con- 
tain high percentages of sodium salts. 

"Near the close of the period the high evaporation 
seems to have so reduced the sea that parts of it became 
isolated lakes and from these brackish deposits were 
precipitated the salts and gj-psum in question. 

"The Green River formation is composed essentially 
of light-colored thinly laminated beds, characterized by 
light-colored thin bedded shales. In appearance these 
shales of the Green River fonnation are much like those 
of the Mancos, especially some of the light-colored and 
thinner beds. 

"The Green River shales weather into a series of 'bad 
lands, and it is not an unusual thing to have a large area 
entirely devoid of plants." 

Arms of the Ocean. — Many soils have been formed by 
deltas of streams deposited in the ocean. These sometimes 
enclose portions of the ocean which may be shut off from 
the main body of water. The inclosed salt water gradually 
evaporates and leaves deposits of soluble salts or an alkali 
condition in the soil. This may be either a surface ac- 
cumulation that is comparatively easy to remove, or the 
salts may extend to considerable depth and be very difficult 
to handle. The type depends on the way in which the 
soil was laid down and the nature of the area of inclosed 
sea water. Subsequent deposits of soil may leave the 
alkali at considerable depths. The alkali land of the 
lower Nile Valley as well as the small alkali tract along 



28 THE ORIGIN OF ALKALI 

the coast of Southern CaHfornia derived their soluble 
salts from ocean water, which was inclosed in arms shut 
off from the main body of the ocean. 

Evaporation of Saline Lakes. — In arid countries nu- 
merous lakes without an outlet to the sea are found. All 
the water running into them is evaporated leaving the 
dissolved material to be gradually concentrated until the 
waters become saturated. Around the bodies of these 
lakes the soil is likely to be high in soluble salts. Arms of 
the lake may be shut off in the manner already described. 
These become centers of local salt accumulation. The 
lands for some distance surrounding these saline lakes are 
likely to be somewhat impregnated with alkali, but as the 
water is approached the concentration is generally in- 
creased. There is usually a fringe near the lake that is 
entirely unproductive. This is surrounded by a zone in 
which only alkali-resistant plants grow, and still farther 
away the less-resistant plants are found. The Great Salt 
Lake in Utah is an example of this kind. 

Formation of Soluble Carbonates. — On account of their 
soluble action on the organic matter of the soil and the 
hard crust which they form on the soil, the soluble car- 
bonates are, of all the soluble salts, most to be dreaded. 
Fortunately, they are not so widespread in their occurrence 
as are the chlorides and sulphates. The comparatively 
insoluble carbonates of calcium and magnesium are very 
abundant but, being only slightly soluble, they are seldom 
if ever harmful to plants. 

The exact method of soluble-carbonate formation is not 
well known. Cameron (3), from studies of greasewood 
and the creosote bush, held that these plants are instru- 
mental in converting the neutral salts into carbonates. 
Aladjem (i), from laboratory experiments with soil kept 



FORMATION OF SOLUBLE CARBONATES 29 

in a water-logged condition and to which nitrates were 
added, conckided that sodium carbonate is reachly formed 
from the nitrates in a water-logged soil. 

Treitz (22) concluded from his studies of alkali soils 
of Hungary that the soluble salts found in them are derived 
from the ash constituents of the plants produced on the 
soil and that the first and most necessary condition for 
the formation of sodium compounds, particularly the 
carbonates, is a calcareous subsoil, carbonates of the 
alkali being formed by the action of calcium carbonate on 
the humates, sulphates, and chlorides of the alkalies. 

From a study of water extracts of typical alkah soils 
and of soils to which various salts were added, Cedroits (5) 
concluded that sodium carbonate is not formed in the soil 
by direct reaction between sodium chloride and calcium 
carbonate, but that the sodi.um of the chloride replaces 
other bases — potassium, calcium, and magnesium — in 
humates and silicates, and the latter give up soda to the 
soil solution when the excess of soluble sodium salts is 
removed. 

Kelley (13) and Breazeale (2) have concluded that 
sodium nitrate reacts with calcium carbonate in the for- 
mation of small quantities of sodium carbonate. In dis- 
cussing this reaction Breazeale has the following to say: 
"In the reaction between sodium nitrate (or sodium 
chloride or sodium sulphate) and calcium carbonate, 
resulting in the formation of sodium carbonate, the presence 
of relatively small amounts of calcium nitrate or calcium 
chloride in the reaction impedes and may prevent the 
formation of sodium carbonate. The presence of a satu- 
rated solution of calcium sulphate in this reaction does 
not entirely stop the formation of sodium carbonate. 
Sodium nitrate, sodium chloride, and sodium sulphate in 



30 THE ORIGIN OF ALKALI 

the presence of carbon dioxide react with calcium carbonate, 
with the formation of sodium bicarbonate. The presence 
of relatively small amounts of calcium nitrate or calcium 
chloride in this reaction impedes and finally prevents the 
formation of sodium bicarbonate. The presence of cal- 
cium sulphate has no efifect in preventing the formation 
of sodium bicarbonate when sodium sulphate, or a mixture 
containing sodium sulphate, reacts with calcium carbonate. 
Sodium nitrate, sodium chloride, and sodium sulphate 
react with calcium carbonate in the soil with the formation 
of sodium carbonate (black alkali)." 

Nitrate Formation. — In alkali areas in many parts of 
several western states, certain brown-colored spots are 
found to contain large quantities of nitrates. Headden 
(lo, ii) and Sackett and Isham (15) believe that these 
nitrates are formed within the soil by the action of non- 
symbiotic nitrogen-fixing bacteria. Stewart and Greaves 
and Stewart and Peterson (17, 16, 18) are convinced, 
however, that large quantities of nitrates seep into the 
soil with the other salts from the country rock and that 
local nitrogen fixation is a minor matter in the accumulation 
of sodium nitrate in alkali soils. 

Localization mentioned by Headden is claimed by him 
to preclude the theory of transportation and concentration 
in some cases. He states that certain of the spots are in 
the center of the valley the soil of which is so deep as to 
preclude the theory of transportation. He also says the 
ground water about and beneath the spots is not high in 
nitrates, which again apparently contradicts Stewart and 
Peterson's theory. 

Concentration by Irrigation Water. — Whatever the 
original source of alkali in the soil, one fact has been well 
demonstrated. The condition may be greatly aggravated 



CONCENTRATION BY IRRIGATION WATER 31 

by the improper use of irrigation water. The author (8) 
and many other workers have shown that the soluble salts 
arc carried ihrou^^di the soil very readily by irrigation 
water. In some soils, like those in parts of the large in- 
terior valleys of California, the original salt content, 
though high, was not sufficiently high to prohibit the 
growth of crops. After irrigation the salts are leached 
from the higher land and carried to the lower, here to be 
concentrated at the surface until the amount becomes too 
great for ordinary crops to grow successfully. This con- 
dition is found to an extent in practically every large 
irrigated section of the world. Methods of preventing 
accumulation in this way will be more fully discussed in 
a later chapter. 

Considerable salt may also be added directly to the 
land by the use of irrigation water carrying large quantities 
of soluble salts. This method of contamination is dis- 
cussed rather fully in Chapter XV. 

Relation of Origin to Methods of Treatment. — An 
understanding of the origin of the alkali in a given area 
is essential to an intelligent treatment of the condition. 
This is as true in handling a soil as in treating a human 
disease. A physician who would give a remedy for a 
headache without seeking the cause of the trouble might 
entirely fail in curing. He might in any case give some 
simple treatment that w^ould be harmless, but a really 
intelligent treatment would be founded on a knowledge 
of the cause of the trouble. Likewise in handling alkali 
land the source of the salt should be known. 

In one region an irrigation canal passed through a shale 
hill that was very high in soluble salts. Large quantities 
were dissolved and taken directly into the stream. Seepage 
was also excessive and much alkali was carried to the 



32 THE ORIGIN OF ALKALI 

lower land by the seepage water. The land was finally 
drained, but the alkali content of the soil was not reduced 
since the quantity added was greater than that lost by 
drainage. Lining the canal through the alkali-charged 
shale corrected the entire matter. Soil experts and drain- 
age engineers, before deciding on the methods of reclaim- 
ing any alkali tract, should discover all probable sources 
of the alkali in the area under consideration and select 
their methods of reclamation accordingly. 

REFERENCES 

1. Aladjem, R. Decomposition of Nitrates as a Possible Cause of For- 

mation of Sodium Carbonates in Egyptian Soils. Cairo Sci. Jour. 6 
(1912), No. 75, pp. 301-302. 

2. Breazeale, J. F. Formation of Black Alkali (Sodium Carbonate) 

in Calcareous Soils. Jour. Agr. Res. 10 (Sept. 10, 1917), pp. 541- 
59°- 

3. Cameron, F. K. Formation of Sodium Carbonate, or Black Alkali, 

by Plants. U. S. D. A. Rpt. No. 71 (1902), pp. 61-70. 

4. Cameron, F. K. The Soil Solution, pp. 1 10-125. (Easton, Pa. 

1911.) 

5. Cedroits, K. K. Colloid Chemistry in the Study of Soils. Russ. 

Jour. Exp. Landvv. 13 (1912), pp. 363-420. (Abs. E. S. R. 28, 
p. 516.) 

6. Clarke, F. W. The Data of Geochemistry. U. S. Geol. Survey, 

Bui. 616 (1916), pp. 22-35. 

7. DoRSEY, C. W. Alkali Soils of the United States. U. S. D. A. Bur. 

of Soils, Bui. 35 (1906), 196 pp. 

8. Harris, F. S. The Movement of Soluble Salts with the Soil Moisture 

Utah Sta. Bui. 139 (1915), pp. 119-124. 

9. Headuen, W. p. Alkahes in Colorado (including Nitrates). Colo. 

Sta. Bui. 239 (1918), 58 pp. 

10. Headden, W. p. The Fixation of Nitrogen in Some Colorado Soils. 

Colo. Sta. Bui. 186 (1913), pp. 3-47. 

11. Headden, W. P. The Fixation of Nitrogen. Colo. Sta. Buls. 155 

(1910), 48 pp. and 178 (1911), pp. 3-96. 

12. Hilgard, E. W. Soils, pp. 422-423. (New York, 1906.) 

13. Kelley, W. P. The Effects of Nitrate of Soda on Soils. Cal. Sta. 

Rpt. 1916, p. 59. 



rp:ferenci:s 33 

14. Knight, W. C, and Slossok, E. C. Alkali Lakes and Deposits. 

Wyo. Sta. Bui. 49 (1901), pp. 75-79. 

15. Sackett, W. G., and Isham, R. M. Origin of the "Niter Spots" 

in Certain Western Soils. Science, n. ser. 42 (1915), pp. 452-453. 

16. Stewart, R., and Peterson, W. Further Studies of the Nitric 

Nitrogen Content of the Country Rock. Utah Sta. Bui. 150 (1917), 
20 pp. 

17. Stewart, R., and Peterson, W. The Nitric Nitrogen Content of the 

Country Rock. Utah Sta. Bui. 134 (1914), pp. 421-465. 
Stewart, R., and Greaves, J. E. The Movement of Nitric Nitro- 
gen in Soil and Its Relation to "Nitrogen Tixation." Utah Sta. 
Bui. 114 (1911), pp. 181-194. 

18. Stewart, R., and Peterson, W. Origin of Alkali. Jour. Agr. Res. 

Vol. 10 (Aug. 13, 1917), pp. 331-353- 

19. Stewart, R., and Peterson, W. The Origin of "Niter Spots" in 

Certain Western Soils. Jour. Am. Soc. Agron. Vol. 6 (1915), 
pp. 241-248. 

20. Traphagen, F. W. The Alkali Soils of Montana. Mont. Sta. Bui. 

18 (1898), pp. 22-23. 

21. Traphagen, F. W. The AlkaH Soils of Montana. Mont. Sta. Bui. 

54 (1904), PP- 91-93- 

22. Treitz, P. The Alkali Soils of the Great Hungarian Alfold -Foldtani 

Kozlony, 38 (1908), pp. 106-131. (Abs. E. S. R. 20, p. 818.) 

23. Whitney, M., and Means, T. H. The Alkali Soils of the Yellowstone 

Valley. U. S. D. A. Bur. of Soils, Bui. 14 (1898), pp. 9-20. 



CHAPTER IV 
NATURE OF ALKALI INJURY TO THE PLANT 

Many of the general effects of excessive quantities of 
soluble salts in the soil are well known, but there still 
remain to be worked out a number of important problems, 
the solution of which will throw a great deal of light on the 
exact nature of alkali injury. Every farmer in alkali 
regions recognizes by the appearance of the soil and the 
limitations in crop growth the presence of alkali, but the 
actual underlying causes of the abnormal conditions are in 
part a mystery to even the most profound students of the 
subject. 

Prevention of Water Absorption. — Doubtless one of 
the very important injuries caused by alkali results from 
checked absorption of water by plants. It matters not 
how desirable other conditions are — how much plant- 
food is available, how deep the soil, or how favorable the 
temperature — if the plant cannot secure water it can make 
no growth. Roots absorb water from the soil by the 
process of osmosis. Because the cell-sap of root-hairs 
contains a stronger solution than the soil, water passes 
through the cell-wall and plasma membrane into the cell 
where it assists in the vital processes of the plant. Since 
carbohydrates are constantly being elaborated in the 
leaves, the cell-sap farthest from the roots is more con- 
centrated than that which has recently been diluted in the 
roots by the entrance of water from the soil. The transpi- 

34 



PREVENTION OF WATER ABSORPTION 35 





Fig. 3. — Upper, Normal Plant Cell. Lower, Cell 

THAT HAS BEEN PlASMOLYZED. 

ration of water from the leaves also tends to concentrate 
the cell-sap in the leaves. This continuous diluting in 
the roots and concentration in the leaves causes a move- 
ment of water from root cells upward toward the leaf 



36 NATURE OF ALKALI INJURY TO THE PLANT 

cells. This movement is necessary to the normal function- 
ing of plants. An ordinary plant, such as wheat, absorbs 
and transpires several times its own weight of water each 
day. Should this movement be reduced, the growth of 
the plant is retarded. If it is entirely shut off the plant 
dies, as pointed out by Pfeffer (12). 

The exact action that takes place when a plant cell comes 
in contact with a solution more concentrated than its own 
content was long ago pointed out by deVries (15) and 
Pfeffer (11). Water passes out of the cell and the plasma 
membrane draws away from the cell-wall leaving the cell 
in a plasmolyzed condition. The rapidity of plasmolysis 
depends on the relative concentration of the solution 
inside and outside of the cell. So well known is this 
phenomenon that the method is used constantly in de- 
termining the concentration of the cell-sap under various 
conditions. 

The above conception helps to explain the observed 
action of plants. The soil solution of land high in alkali is 
stronger than the cell-sap; therefore, no plant growth 
takes place. In other land where there is less alkali, the 
concentration may be just strong enough to reduce the 
rate of water absorption but not enough to shut it off 
entirely. Under this condition the crop yield would be 
reduced. Thus, every gradation from a normal crop to 
no crop at all may be found in a single field. 

Under some conditions, such as after irrigation or heavy 
rains, alkali may be so diffused throughout the soil that the 
concentration at any point is not sufficient to prevent the 
crop from beginning a good growth. As the season ad- 
vances, the salt may accumulate at the surface of the 
soil until irrigation water is applied. It may then be 
washed down to the roots in a concentrated form causing 



EFFECTS ON GERMINATION 37 

the death of the plant. The farmer says his crop has been 
burned since it has that appearance. As a matter of fact 
water may have been drawn out of the plant through the 
roots. This, taken with the loss by transpiration, des- 
sicates the plant to the point at which it dies. 

Effects on Germination. — Before a:* seed can germinate 
it must absorb water. Ordinarily when a seed is planted 
in a moist soil it absorbs moisture and swells. At once 



'"Tff ''■!'} I I 




l-'iG. 4. — An Orchard Planted on Land that Came from a Formation 
High in Soluble Salts. The Salts h.vd Killed Most of the Trees 
BY the Second Year. 



the enzymes contained in the seed convert part of the 
starch into sugar which increases the strength of the solu- 
tion in the seed. This in turn hastens absorption and the 
seed soon contains sufficient moisture with which to carry 
on rapid cell division and growth. Within a few days a 
root is sent out, then a shoot for the top, and a new plant 
is growing. 

When a seed is placed in a strong salt solution or a soil 
that has a large amount of alkali, it does not absorb mois- 
ture; consequently, it lies dormant the same as it would in 
dry soil or in dry air. The coating on the seed protects it 
from absorbing most of the salts. It may not be injured, 
and as pointed out by Slosson (13) it will germinate when 
removed from the alkali soil to conditions favoring ger- 



38 NATURE OF ALKALI INJURY TO THE PLANT 

mination. Under similar conditions, a plant would not 
only be hindered from growing, but would actually be 
killed. 

A salt solution not sufficiently strong to prevent entirely 
the germination of seeds may greatly delay it. The author 
has shown (3) that seeds which normally germinate in six 
days may be delayed as long as twenty-one days under 
conditions in every way similar except in the salt content of 
the soil. This delayed germination may be very serious 
in regions where the normal length of the growing season 
is greater than that required for maturity of the crop even 
if growth after germination were satisfactory. 

Effect on Structure of the Plant. — Vegetation growing 
on alkaU soil has a characteristic appearance similar to 
that found growing under desert conditions. It generally 
lacks that bright green appearance of vigorous and healthy 
growth. This condition is observed even in water-logged 
land where there is an ample supply of moisture. A 
similar moisture supply without alkali would result in a 
succulent growth. 

Harter (4) examined the structure of plants to determine 
the effect of soluble salts in the soil. He found that culture 
in a soil containing considerable quantities of sodium 
chloride together with other salts produced measurable 
changes in the leaf structure of wheat, oats, and barley. 
The most notable modification produced was the conspicu- 
ous bloom or waxy deposit that formed on the surface of 
the leaves. This development of bloom was accompanied 
by an easily measured increase in the thickness of the cuticle 
and outer walls of the epidermal cells and by a marked 
decrease in their size. 

In regard to transpiration of the plants, it was found 
that when the alkali salts are present in sufficient con- 



INJURY AT THE SURFACE OF THE SOH. 39 

centration to cause the modilications of structure noted, 
transpiration is much reduced. On the other hand, the 
same salts when present in amounts too small to produce 
any measurable influence upon structure have a decidedly 
stimulating elTect upon transpiration. 





Fig. s. — The Lo^\^LR Part of an Orchard beixg Killed by 
Alkali brought to the Surface by a Rising Water Table. 

Similar modifications in structure have been pointed 
out by Kearney (7) who shows that thickness of leaves and 
stems with zerophytic tendencies characterizes plants 
growing in a saline soil. 

Injury at the Surface of the Soil. — Orchards and \ine- 
yards in many cases ha\'e been planted in soils containing 
a rather high salt content, but not high enough to prevent 
growth. A root system may become thoroughly estab- 
lished in an untoxic lower layer of soil which is slightly 



40 NATURE OF ALKALI INJURY TO THE PLANT 

alkaline and yet there may be a gradual accumulation of 
salt at the surface of the soil. This condition has the 
effect of corroding the plant and it often destroys the bark 
so thoroughly that the passage of elaborated food from 
leaves to roots is prevented. This injury is rather limited 
in the total damage done and may be overcome without 
great expense. 

Formerly it was thought that the principal injury to 
vegetation by alkali resulted from a corroding action. 
This is probably not the case, with the possible exception 
of the carbonates. The carbonates, in addition to any 
direct action on the plant itself, make the soil hard and a 
poor medium for the plant. 



REFERENCES 

1. Breazeale, J. F. Effect of Sodium Salts in Water Cultures on the 

Absorption of Plant-food by Wheat Seedlings. Jour. Agr. Res. 7 
(1916), pp. 407-416. 

2. DuGGAR, B. M. Plant Physiology, pp. 64-83. (New York, 191 1.) 

3. Harris, F. S. Effect of Alkali Salts in Soils on the Germination and 

Growth of Crops. Jour. Agr. Res. 5 (1915), pp. 1-52. 

4. Harter, L. L. Influence of a Mixture of Soluble Salts, principally 

Sodium Chloride, upon the Leaf Structure and Transpiration of 
Wheat, Oats, and Barley. U. S. D. A. Bur. PI. Ind. Bui. 134 (1908), 
19 pp. 

5. Hicks, G. H. The Germination of Seeds as Affected by Certain Chemi- 

cal Fertilizers. U. S. D. A. Div. Botany, Bui. 24 (1900), 15 pp. 

6. Hilgard, E. W. Soils, pp. 326-428. (New York, 1906.) 

7. Kearney, T. H., and Cameron, F. K. Some Mutual Relations be- 

tween Alkali, Soils, and Vegetation. U. S. D. A. Rpt. 71 (1902), 
60 pp. 
S. JosT, L. Plant Physiology, pp. 11-35. (Oxford, 1907.) 
9. Kearney, T. H. Plant Life in Saline Soils. Jour. Wash. Acad, of 

Sci. Vol. 8 (1918). 
10. MiCHEELS, H. The Mode of Action of Weak Solutions of Electro- 
lytes on Germination. Acad. Roy. Belg. CI. Soc. (1912), No. 11, 
pp. 753-765- (Abs. E. S. R. 29, p. 218.) 



REFERENCES 41 

II. Pfeffer, W. Osmotischc UnlcTsiKluin^en (1S77), 236 pp. 
1.'. Pfeffer, W. Physiology of Plants, Vol. i (1900), pp. 90-107; Vol. 2 
(1903), pp. 249-258. 

13. Slosson, E. E. Alkali SLudics. W'yo. Sla. Rpt. 1S99, 29 p[). 

14. True, R. H. The Physiological Action of Certain Plasmolyzing 

Agents. Bot. Gaz. Vol. 26 (1898), pp. 407-416. 

15. Vries, H. de. Eine Methode zur Analyse der Turgorkraft. Jahr. 

f. wiss. Bot. 14 (1884), pp. 427-601. 



CHAPTER V 
TOXIC LIMITS OF ALKALI 

Numerous attempts have been made to determine the 
approximate quantity of the different alkali salts, both 
singly and in various combinations, which may be with- 
stood successfully by crops. Some experimenters have 
confined their work almost entirely to held observations. 
Others have worked with natural alkaU soils from the 
fields or soils made alkaline by the addition of salts in 
definite quantities and sown to crops under laboratory 
conditions. Still others have used different solutions 
containing salts as the medium for determining the toxicity 
of salts to plants. Each method has both advantages and 
disadvantages. 

The field work has often been done by sampling soils 
showing injury to plants and also adjoining soils where 
the effects of the alkali could not be detected. These 
observations are usually taken after the crop has made 
considerable growth, when the extent of injury may be 
estimated by the appearance of the plants. Such deter- 
minations may not take into consideration conditions pre- 
vailing during the earlier stages of growth. The vigor and 
deHcacy of the plant at the time the alkali comes in contact 
with it appear to have much to do with its tolerance. 
Alfalfa, sugar-beets, and a number of other plants do not 
withstand alkali well in their seedling stages, but are 
among the most tolerant during later stages of growth. 
Most plants do better under alkali conditions as maturity 

42 



XUTRlEXr SOLUTIONS 43 

ajiproaches. Since the conditions under which plants 
grow at different times is modified by rainfall, movement 
of ground water, evaporation, and other factors, an analvsis 
of the soils at a particular period of growth is not so definite 
for indicating toxicity as might be wished. Because of 
the difficulty in fixing definite toxic limits under field 
conditions, these observations will not be considered in 
the present discussion but will be reserved for Chapter XIV 
dealing with crops for alkali land. 

Toxicity in Solution. — Some of the first attempts to 
establish the toxic limits of alkali were made in solution 
cultures because the solution was easy to make up, easy 
to analyze subsequently where it was desired to learn the 
final concentration of the water, and because such com- 
plicating factors as absorption of the salts, moisture con- 
tent of the soil, and nature of the soil were eliminated. 
Some of the experiments were carried on in cultural media, 
such as Knop's solution, in an attem.pt to duphcate soil 
conditions as nearly as possible, whereas others were made 
in water containing only alkali salts. 

Nutrient Solutions. — Some of the nutrient-solution 
cultures were carried to later stages of growth than those 
with the toxic salts alone. Since, however, the strength 
of the nutrient solution, its composition, and other factors 
modify the results almost as much in some cases as the 
alkali salts the advantages of the culture media over the 
simple solutions are not so apparent. Plants are usually 
at their most critical life period in the seedling stages 
where they are still depending on the seed for their nu- 
trition. The results of LeClerc and Breazeale (17) show 
the tolerance of wheat seedlings for sodium chloride in 
culture solutions to be about 3000 parts per million, 
which is not essentially different from certain other results 



44 TOXIC LIMITS OF ALKALI 

where the solution containing the alkali salts was tap 
water. Tottingham (29) did not find the introduction of 
potassium chloride or sodium chloride into Knop's solution 
to have any marked effect on wheat plants, although the 
sodium chloride depressed the dry weight and length of 
roots of buckwheat. 

Alkali Solutions. — - Alkali solutions have been used in 
a number of different ways to determine toxicity. Some 
experimenters have germinated the seed in the alkali solu- 
tions; others have used the alkali solutions in which to 
immerse the roots of the seedlings after they have germi- 
nated under normal conditions. Since conditions differ 
so widely under the two methods and because the time 
allowed for the alkali to become effective differs consider- 
ably, the two methods will be treated separately. 

Seed Germination. — Experiments with wheat in 
Wyoming (4, 27) show that salts hinder the absorption 
of water by the seed so that germination is retarded and 
that the kind of neutral salt is of less importance than the 
osmotic pressure of the solution. The work of Kearney 
and Cameron (14) on antagonism and of the author (10) 
apparently disprove the latter statement, however. From 
the Wyoming experiments which included salt solutions 
from 1000 to 90,000 parts per million in strength, it was 
found that inhibition was not retarded in as rapid pro- 
portion as the osmotic pressure of the solution was in- 
creased. Inhibition was apparently not influenced by the 
vitahty of the seed nor did the salts affect the vitahty of 
the seed when removed before sprouting. The weaker 
solutions up to 4000 parts per million of sodium sulphate, 
sodium chloride, magnesium sulphate, or sodium car- 
bonate had a beneficial effect on the germination of the 
seed and the growth of the plants. 



SEED GERMINATION 45 

Miss ]\Iago\van (iq) states that alkali experiments are 
not reliable when they are continued only a week because 
the relative toxicity of the salts may change later. She 
found that although magnesium chloride was at first the 
most toxic of the chlorides, followed by sochum chloride, 
potassium chloride, and calcium chloride, this relation- 
ship did not hold throughout the experiment. 

Working with wheat seedlings in solutions of o.oi normal, 
or 585 parts per million, sodium chloride, 850 parts per 
million sodium nitrate, 746 parts per million potassium 
chloride, and loii parts per million potassium nitrate, 
]\Iicheels (21) found chlorine more harmful than nitrate 
ions, and sodium more harmful than potassium ions. He 
ascribed the variation to physiological and not chemical 
differences, as did also Slosson and Buffum (27) working 
with wheat, rye, and beans in the common alkali salt 
solutions. Sodium carbonate was the only salt found 
causing other than physiological injury. 

Wyoming experiments (27) show the highest concentra- 
tion of salts not retarding germination of wheat and rye 
to be as follows: 

MgS04 Na2S04 NaCl Na.COa 

Wheat 10,000 7000 4000 4000 

Rye 10,000 7000 4000 1000 

The vitality and time to germinate were effected dele- 
teriously as the strength increased above the minimum. 
Rye was as a general rule more tolerant of the higher 
concentrations of these salts than was wheat. 

Sigmund (26) found 5000 parts per million of sodium 
chloride or of sodium carbonate retarded the germination 
of cereal seeds in . solutions of these salts. Vetch and 
rape seeds were killed in 5000 parts per million solutions 



46 TOXIC LIMITS OF ALKALI 

of sodium carbonate, but neither they nor wheat were 
injured in 5000 parts i)er million of sodium bicarbonate. 
According to this author the highest strength of sodium 
chloride endurable by the cereals was 5000 parts per mil- 
lion, by legumes 3000 parts per million, and by rape 1000 
parts per million. Jarius, as quoted by Kearney and 
Cameron (14), reports a stimulating effect on seeds of 
wheat, rye, rape, maize, beans, and vetch in a solution 
containing 4000 parts per milhon of sodium chloride. 
Storp, as quoted from Kearney and Cameron (14), found 
this salt to stimulate germination in solutions as strong as 
100 parts per million. In his w^ork with solutions of sodium 
chloride in concentrations ranging from 1250 to 50,000 
parts per million, Coupin (6) found the toxic hmits for 
wheat to be 18,000 parts per million, of lupine 22,000 parts 
per million, of maize 14,000 parts per million, of peas 12,000 
parts per million, and of vetch 11,000 parts per million. 
In this author's experiment the endurance of the plant as 
a whole to the solution was taken to indicate the limit, 
whereas with some of the others the death of the root or 
some other part is sometimes taken to indicate the injury 
to the plant. He found the toxic limits for seashore plants 
to be several times that for the crop plants mentioned 
above. Nessler, who is quoted by Hicks (12), states that 
hemp seed was injured in germinating by 2500 parts per 
million of sodium chloride, clover by 5000 parts per mil- 
lion, and wheat by 10,000 parts per million. Rape seed 
was found to resist sodium chloride, potassium chloride, 
calcium nitrate, sodium nitrate, and potassium sulphate 
in concentrations as high as 5000 parts per million, but 
the vitality of wheat, rye, maize, beans, and peas was 
seriously injured when using solutions as strong as this (12). 
Sodium chloride had a stimulating effect. 



SEEDLINGS IN ALKALINE SOLUTIONS 47 

Seedling Transference into Alkaline Solutions. This 
practice has been preferred to germinating and growing 
the plants in the alkaHne sokitions by some investigators. 
Certain experiments ha\e indicated that plants may 
gradually become accustomed to salts as they grow older 
so that the injurious strength of solution at one period 
may not be so at another. By dipping the seedlings into 
the alkali solutions at a definite period after germinating, 
it has been hoped that a better standard for comparing 
toxicity would be fixed. Fcr such work many standard 
conditions have been suggested but few of these standards 
have been accepted by other workers, so there is a wide 
difference in the conditions under which the toxicity of 
the plants have been determined. 

In the experiments of Kearney (13) and his co-workers 
the roots of the seedlings were placed in the alkali solu- 
tions for twenty-four hours and the death of the root tip 
was taken to indicate the toxic limit for the plant. As 
a result of this work, corn showed the toxic effect of mag- 
nesium less than other salts, but with lupines, alfalfa, wheat, 
sorghum, oats, cotton, and beets the magnesium compounds 
were considerably more toxic than other salts. The sodium 
chloride and sodium sulphate did not differ greatly in 
toxicity to the different plants in several cases, and the 
sodium carbonate was several times more toxic than these 
two salts in most cases. Corn, which is considered rather 
sensitive to alkah, endured more sodium carbonate than 
the other crops, whereas sorghum, cotton, and beets, 
which are usually resistant in soils, were affected most 
by this salt in solution. The limits for wheat were 650 
parts per million of sodium carbonate, 2610 parts per 
million of sodium chloride, and 2830 parts per million of 
sodium sulphate. Comparing the two series with lupines 



48 TOXIC LIMITS OF ALKALI 

it is seen that the variations are wide. In another experi- 
ment with lupine, where growth was prevented by the 
salts contained in the solutions, the magnesium salts were 
not so toxic as the carbonates of sodium, and the mag- 
nesium sulphate was the least toxic of all salts. This 
shows that very wide differences might be expected ac- 
cording to the method employed. 

True (30), using the above method for obtaining the 
toxic limit of lupine in sodium chloride solutions found 
it to be 3625 parts per million, which again shows the 
possible error. Coupin (5) allowed the plants to remain 
in the solutions until the whole plant showed the salts 
to be causing injury. His limits for lupine using sodium 
chloride, magnesium chloride, and magnesium sulphate 
were 12,000, 8000, and 10,000 parts per million for the 
respective solutions, which is about the same as the 
above results where growth was prevented. 

The resistance here is several times that found by Harter 
where the first injury was the point of indication rather 
than the death of the plant. Allowing the roots to remain 
in the salt solution twenty-one days and then weighing, 
the author (10) found wheat seedlings to produce about 
one-half as much as the check in the solutions containing 
5000 parts per million of sodium carbonate, or in those 
containing over 10,000 parts per million of sodium chloride 
or sodium sulphate. Haselhoff (q) concluded that growth 
might be inhibited with a 5000-parts-per-million solution 
of sodium chloride and injury would result in the presence 
of 500 parts per million. 

Hansteen (8) states that 5000 parts per million of salts 
other than calcium are injurious when used singly, but 
when combined with lime the injury is greatly diminished. 
Others have found the same antagonistic effects of dif- 



IN SAND 49 

ferent salts. This subject is reserved for Chapter VIII 
and will not be discussed here. 

A series of experiments was made by Marchal (20) to 
discover the effect of salts on the bacterial activities of 
tlic nodules of pea roots. He found alkaline nitrates in 
concentrations of 100 parts per million checked the tu- 
bercle production in water cultures. Ammonium salts 
were injurious in concentrations of 500 parts per million. 
Potassium salts at 5000 parts per million and sodium 
salts at T,^;^^ parts per million tended to retard symbiosis, 
Ijut calcium and magnesium salts favored it. 

Soil Results. — Soil studies of alkali have been found 
to show less variation for Like treatment than solution 
studies. Some of the other disadvantages of solution 
studies of the effect of alkali on the higher plants are that 
the seed in germination tests and the root system are placed 
in an unnatural environment, the air circulation being 
eliminated and the normal resistance of the soil being 
changed. Studies of plants in solutions compared with 
similar soil cultures have shown that physiological dis- 
turbances are more likely to occur in solutions than in 
soils; the root-hairs are less numerous and the roots grow 
longer and thinner in the solution than in the soil. In- 
dividuals show much more variation due to unfavorable 
causes in the solutions than in the soils even where the 
soil consists of sand containing practically no nourishment. 

In Sand. — The physical conditions under which the 
plants grow seem to have some influence on their natural 
development. The author (10) found that whereas wheat 
seedlings produced about a half normal crop of dry matter 
in a sand containing 1000 parts per million of sodium 
chloride in solution cultures, more than half a normal 
crop was obtained when the concentration was over 10,000 



50 



TOXIC LIMITS OF ALKALI 



parts per million of this salt. For sodium carbonate the 
relationship between sand and solution cultures was about 
looo and 5000 parts per million, respectively, and for 
sodium sulphate it was about 5000 to over 10,000 parts 
per million, respectively, for half-normal crops of dry 
matter. Le Clerc and Breazeale (17) found wheat seed- 
lings more tolerant for sodium chloride in sand than in 
solution. Breazeale (2) states that the reverse relation- 




i'lG. 0. 



Experiments tu Determine the Toxicity of 
Various Alkali Salts. 



ship for nutrient solutions holds, 300 parts per million of 
nutrient solution being the best concentration for wheat 
seedlings, while 2500 parts per million was best for them in 
sand. Others have found the latter relationship to hold 
for sand. The size of pure quartz sand particles ap- 
parently had no effect on the toxicity of alkali in tests 
made by Harris and Pittman (11), but the quantity of 
moisture in the soil had considerable influence. 

The differences which may be expected in alkali experi- 
ments with differing moisture contents are shown in tests 



IN SAND 51 

made by the author (lo). 'J'he toxic limits of wheat for 
salts in a sand were as follows: sodium chloride with 12 
per cent moisture 2900 parts per millon, with 18 per cent 
57C0 parts per million; sodium carbonate with 12 per cent 
2700 parts per million, with 21 per cent 3300 parts per 
million; sodium sulphate with 12 per cent 8000 parts per 
million, with 24 per cent 16,000 parts per million. When 
the salts were added dry to the soil rather than in solution 
as in the above experiments, the limits of tolerance were 
higher, but the quantity of moisture added to the soils 
would influence the permissible quantity even more in 
such experiments than where the solutions were added be- 
cause the quantity dissolved would be more dependent on 
the water present. 

In the work of Buffum and Slosson (4) sand was used as 
the medium for growing seed in a nutrient solution, an 
attempt being made to duplicate soil conditions as nearly 
as possible. Their work was with wheat and alfalfa in 
sand containing solutions with osmotic pressure equivalent 
to 2.03, 3.80, and 7.10 atmospheres which corresponds to 
5000, 10,060, and 20,000 parts per million of sodium sul- 
phate, or 2700, 5100, and 9700 parts per million of sodium 
chloride. The conclusions were that the lower concentra- 
tions of the salts were stimulating to the plants bu:, that 
the higher ones were harmful. Solutions of sodium sul- 
phate, potassium sulphate, sodium chloride, and potassium 
chloride were all about equally harmful to those plants at 
the same osmotic pressures when based on germination 
and several other observations of the growing plants. 

A series of germination experiments in a sand by Stew- 
art (28) showed that 10,000 parts per million of sodium 
sulphate was generally fatal to seeds of barley, rye, wheat, 
oats, peas, alfalfa, and red and white clovers. The re- 



52 TOXIC LIMITS OF ALKALI 

sistance of the plants was about in the order given, barley 
being most tolerant. About 5000 parts per million of 
sodium carbonate or sodium chloride was fatal to the 
germination of these plants, and, excepting that peas 
were the most resistant to sodium carbonate and alfalfa 
was weakest for those salts, the order of toxicity was 
about as given above. 

Oats and mustard were found more resistant than flax 
for sodium chloride and sodium sulphate in pots of sand 
containing 315 to 1889 parts per million of these salts. 
Some influence of sodium sulphate was perceptible at the 
higher concentrations and the sodium chloride caused 
injury to the oats and mustard in the larger quantities. 
Wheat, oats, and peas failed to grow in soils containing 350 
parts per million of chlorides but survived in the presence 
of 10,000 parts per million of total salts. Wheat and oats 
could withstand 20,000 parts per million of total salts 
where the chlorine content was less than 1250 parts per 
million. 

Claudel and Crochetelle (12) found that sodium nitrate 
in concentrations of 2000 parts per million prevented the 
germination of buckwheat and beans, injured or checked 
the germination of beet seed, and badly injured those of 
clover. However, it had very little effect on wheat and bar- 
ley seed. Buckwheat was considerably, and clover slightly, 
affected by 1000 parts per million. Barley was the only 
crop able to withstand 5000 parts per million of this salt. 

From the above discussion of the effects of alkali in 
sand on plants, it is seen that where allowance is made for 
the difference in the method of arrivmg at the toxic limits, 
the results are fairly uniform when compared with those 
of solution determinations. The two salts, sodium car- 
bonate and sodium chloride, are nearly the same in toxicity, 



IN LOAM SOIL 53 

while sodium sulphate is considerably less harmful than 
the former two salts. 

In Loam Soil. — From a i)ractical point of view loam 
soil is a much more desirable medium for studying the 
effect of alkali on plants tlian is either sand or a solution. 
Absorption, antagonism, and physical conditions must 
all eventually be taken into consideration before the real 
toxic effect of the salts under normal conditions can be 
arrived at correctly. 

The use of loam, or other soil containing organic matter 
and having high absorptive properties, complicates the 
determination of the toxicity of salts. Harris and Pitt- 
man (ii) found that of two soils containing equal quantities 
of alkali and equivalent moisture contents, wheat on the 
soil with highest organic matter was injured less than 
where the organic matter was about as it is in ordinary 
loam. The organic matter appeared to remove sodium 
carbonate from the soil solution so that tliis salt appeared 
less toxic than has usually been ascribed to it from solu- 
tion or sand cultures or field extraction experiments. 
Wheat plants tolerated more alkali in a loam than in either 
a sand or clay and more in a coarse loam than a finer one 
with the same percentage of moisture, although with 
equivalent moisture contents the coarser loam was less 
tolerant than the liner. The toxicity of the salts de- 
creased with increasing percentages of soil moisture up 
to the maximum moisture content producing good crops. 
Changing the moisture relationship of the soil influenced 
the toxicity of sodium chloride and sodium sulphate more 
than did changing the organic matter, but the organic 
matter had the greater influence for sodium carbonate. 
High organic matter and moisture content offered the 
most favorable conditions for alkali toleration. 



54 TOXIC LIMITS OF ALKALI 

The work of Haselhoff (9) on heavy loam and clay 
soils led him to conclude that because these soils absorb 
chlorine from the solutions of chlorides and thereby gradu- 
ally destroy the physical condition of the soil, the injurious 
influence of chloride solutions on soil productiveness and 
crop yield takes place gradually. 

Le Clerc and Breazeale (17) found the greater tolerance 
of wheat seedlings to sodium chJoride in clay as compared 




'rfrrrrvrrrrf. 



Fig. 7. — Growth of Wheat with Various Concentrations 
OF Different Salts. 

to sand and solution cultures to be due to the lime which 
the clay contained. Shutt (25) found that calcium oxide 
was very effective and calcium carbonate less so in correct- 
ing the toxicity of soil containing 50,000 parts per million 
of magnesium sulphate. Even when calcium oxide was 
used, germination was still retarded but a larger percent- 
age of the plants grew and the growth was more healthy. 
This antagonistic action of calcium and other salts will 
be taken up in greater detail in Chapter VIII. 

In the work done on the germination and growth of 
plants in Wyoming by Buffum (2), alkali soils were leached 
of their alkali and then made up to the required percent- 



IN LOAM SOIL 



55 



age by the addition of the ]3ure salts in one part of the 
experiment and in the other the soil was leached of a por- 
tion of its alkali sufficient to obtain the required alkali 
content. The alkali was two-thirds sodium sulphate and 
one- third magnesium sulphate and in concentrations from 
10,000 to 50,000 parts per million. The test showed that 
in a soil containing 2^ per cent moisture, rye germinated 
almost normally with 22,500 parts per million of these 
salts; barley nearly perfect with 10,000 but less than half 
normal with 22,500 parts per million in the natural alkali 
soil; wheat about two-thirds normal with 10,000 parts 
per million; alfalfa perfect with 10,000 parts per million 
but producing hardly a sprout in 22,500 parts per million; 
while turnips and oats produced less than one-half normal 
germination in soil containing 10,000 parts per million. 
The time taken for the seeds to germinate was increased 
in proportion to the salt present even for the lower quan- 
tities of alkali. 

Table IX summarizes the work of Guthrie and Helms (7) 
in a rich garden loam soil mixed with nearly an equal 
c|uantity of light sand. 



Table IX. Concentrations of 
OF Various 


Salts Affecting the 
Crops 


Grow 


FH 




Sodium Chloride 


Sodium Carbonate 




Wheat 


Barley 


Rye 


Wheat 


Barley 


Rye 


Germination affected 

Germination prevented 

Growth affected 


500 
2000 

500 
2000 


1000 
2500 

1000 
2000 


1000 
4000 

1500 
2000 


3000 
5000 

1000 
4000 


2500 
&000 

1500 
4000 


2500 
5000 

2500 


Growth prevented 


4000 







From the figures it is seen that the resistance of seed to 
alkali during germination is not always the same as the 



56 



TOXIC LIMITS OF ALKALI 



resistance during later growth, and the relation between 
germination and subsequent growth differs for these two 
salts. 

With the following quantities of alkali added to loam 
soil the author (lo) found the plants indicated in the table 
to produce about half-normal crops of dry matter. 

Table X. Quantities of Various Salts Added to the Soil 
WHICH Reduced the Yield of Crops to about Half Normal 



Crop 



Barley 

Oats 

Wheat. : . . . 

Alfalfa 

Sugar-beets . 

Corn 

I'ield peas . . 



Sodium Chloride 



5000 
4000 
3000 
3000 
3000 
3000 
3000 



Sodium Carbonate 



10,000 
8,000 
0,000 
6,000 
6,000 
4,000 
4,000 



Sodium Sulphate 



Above 10,000 

" 10,000 

" 10,000 

" 10,000 

" 10,000 

" 10,000 

" 9,000 



It will be noted that the figures by the author are con- 
siderably above those of Guthrie and Helms, but that the 
carbonates when added to the soil in each case were less 
harmful than the sodium chloride. In the sand soil the 
sodium chloride and sodium carbonate were noted to be 
nearly equally toxic and for the field results presented in 
Chapter XIV the sodium carbonate shows nearly the 
reverse relationsliip to this. The low toxicity of the 
salts as compared with those for field determinations are 
probably due partly to absorption of some of the salts 
and to the even distribution and favorable moisture content 
possible in controlled experiments compared with field 
conditions. Of the salts used in the experiments of the 
author with wheat seedlings, the order of toxicity for salts 
added from highest to lowest was as follows: sodium 
chloride, calcium chloride, potassium chloride, sodium ni- 
trate, magnesium chloride, potassium nitrate, magnesium 



IN LOAM SOIL 57 

nitrate, sodium carbonate, potassium carbonate, sodium 
sulphate, i)otassium suli)hate, and magnesium sulphate. 
This order docs not hold when the concentration is 
determined by an anal}sis of the soil. The anions 
were found to affect the toxicity more than the cation, 
the chloride being the most toxic anion and sodium the 
most toxic cation. 

Bancroft (i), in his work with beans growing in large 
pots to which alkali was added from below after the plants 
were growing until they wilted and died, found the fol- 
lowing quantities of salts just killed the plants: magnesium 
chloride, 2640 parts per million; sodium carbonate, 2710 
parts per million; sodium nitrate, 3700 parts per million; 
sodium chloride, 5660 parts per million; magnesium sul- 
phate, 5820 parts per million; sodium sulphate, 6810 parts 
per million; and sodium bicarbonate, 12,300 parts per 
million. 

In germination tests on sugar-beet seed by Headden 
(Colo. Sta. Bui. 46) it was found that while 1000 parts 
per million of sodium carbonate permitted the seed to 
germinate freely, 5000 parts per million w^as injurious. 
The limit for sodium sulphate was about 8000 and for a 
mixture of the tw^o about the same as the sodium carbonate. 

From the foregoing discussion of the various experi- 
ments with alkali under different conditions and from the 
results given in Chapter XIV on crops for alkali land, it 
is seen that the limits vary so widely because of the dif- 
ferent methods of arriving at these limits, that unless the 
conditions can be duplicated, considerable error might 
result from estimates secured by different experimenters. 
The estimates under field conditions would be expected 
to range through a wider limit because of the complicated 
changes within the soils and because of differences in de- 



58 TOXIC LIMITS OF ALKALI 

termining the salts in the soils. With laboratory experi- 
ments, the same allowances must be made because of the 
various complicating factors such as moisture content, 
organic matter, antagonism of the salts, absorption, and 
differences in tolerance of the plants at different times. 

REFERENCES 

1. Bancroft, R. L. The Alkali Soils of Iowa. Iowa Sta. Bui. 177 

(1918) 

2. Breazeale, J. F. Effect of the Concentration of the Nutrient Solu- 

tion upon Wheat Cultures. Science, n. ser. 22 (1905), pp. 146-149. 

3. Buefum, B. C. Alkali. Wyo. Sta. Bui. 29 (1896), pp. 219-253. 

4. BuFFUM, B. C. Alkali Studies, III. Wyo. Sta. Rpt. 1899, p. 40. 

Also Rpt. for 1900. 

5. CoupiN, H. On the Poisonous Properties ot Compounds of Sodium, 

Potassium, and Ammonium. Rev. Gen. Bot. 12 (1900), No. 137, 
pp. 177-193. (Abs. E. S. R. 12, pp. 717-718.) 

6. CoupiN, H. On the Poisonous Properties of Sodium Chloride and Sea 

Waters toward Plants. Rev. Gen. Bot. 10 (1898), No. 113, pp. 177- 
190, figs. 3. (Abs. E. S. R. II, p. 24.) 

7. Guthrie, F. B., and Helms, R. Pot Experiments to Determine the 

Limits of Endurance of Different Farm Crops for Certain Injurious 
Substances. Agr. Gaz. N. S. Wales, 14 (1903), No. 2, pp. 1 14-120. 
See also 16 (1905). 

8. Hansteen, B. The Relation of Plants to Salts in Soils. Nyt. Mag, 

Naturvidensk. 47 (1909), No. 2, pp. 181-192. (Abs. E. S. R. 23, 
p. 28.) 

9. Haselhoff, E. The Action of Chlorides on Soil and Plant. Fiihling's 

Landw. Ztg., 64 (1915), Nos. 19-20, pp. 478-508. (Abs. E. S. R. 35, 
pp. 423-424.) 

10. Harris, F. S. Effect of Alkali Salts in Soils on the Germination and 

Growth of Crops. Jour. Agr. Res. Vol. 5 (1915), pp. 1-52. 

11. Harris, F. S., and Pittman, D. W. Soil Factors Affecting the To.xic- 

ity of Alkali. Jour. Agr. Res. Vol. 15 (1918), pp. 287-319. 

12. Hicks, G. H. The Germination of Seeds as Affected by Certain 

Chemical Fertilizers. U. S. D. A. Div. Bot. Bui. 24 (1900), p. 15. 

13. Kearney, T. H. The Wilting Coefficient for Plants in Alkali Soils. 

U. S. D. A. Bur. PI. Ind. Cir. 109, pp. 17-25. 

14. Kearney, T. H., and Cameron, F. K. The Effect upon Seeding 

Plants of Certain Components of Alkali Soils. U. S. D. A. Rpt. 71. 
pp. 7-60. 



ri:1'1-:rkxci:s 59 

15. Kearney, T. II., and IIarter, L. L. 'J'hc C'om|)aralivc ToliraiKc of 

Various Plants for the Salts in Alkali Soils. U. S. D. A. Bur. PI. 
Ind. Bui. 113 (1907), p. 18. 

16. Kossovicii, P. Alkali Soil;--: TlK-ir Inllucnce on Plants and the 

Methods of Examining Them. Zhur. Opuitn. Agron. (Jour. K.\p. 
Landw.), 4 (1903), No. i, pp. 1-42. (Ahs. E. S. R. 15, p. 22.) 

17. Le Clerc, J. A., and Brkazeale, J. F. The EfTcct of Lime upon the 

Alkali Tolerance of Wheat Seedlings. Orig. Commun.,8th Internat. 
Cong. .\ppl. Chem. (Washington and New York), 26 (1912), 
Sect. Vla-XIb, app. p. 135. (Abs. E. S. R. 29, p. ^22.) 

18. Lesage, p. The Limits of Germination of Seeds after being Placed 

in Salt Solution. Compt. Rend. Acad. Sci. (Paris), 156 (1913), 
No. 7, pp. 559-562. (Abs. i.. S. R. 29, p. 218.) 

19. Magowan, Florence N. The To.xic Effect of Certain Common 

Salts of the Soil on Plants. Bot. Gaz. 45 (1908), No. i, pp. 45-49. 

20. M.ARCiiAL, E. Influence of Mineral Salts on the Production of Tuber- 

cle on Pea Roots. Compt. Rend. Acad. Sci. (Paris), 133 (1901), 
No. 24, pp. 1032-1033. (.Abs. E. S. R. 13, p. 1017.) 

21. MiCHEELS, H. The Influence of Chlorides and Nitrates of Potassium 

and Sodium on Germinating Plants. Internat. Ztschr. Phys. Chem. 
Biol. I (1914), Nos. 5-6, pp. 412-419. 

22. MiYAKE, K. The Influence of Salts Common in .\Ikali Soils ujxin the 

Growth of the Rice Plant. Jour. BioL Chem. 16 (1913), No. 2, 
pp. 235-263. 

23. MiYAKE, K. The Influence of Acids, Alkalies, and .\lkali Salts on the 

Growth of Rice Plants. Trans. Sopporo Nat. His. Soc. 5 (1913), 
No. I, pp. 91-95; abs. in Bot. Cent. 126 (1914), No. 22, p. 588. 
(Abs. E. S. R. 34, p. 31.) 

24. Reveil. Recherches de physiologic vegetale de Taction des poisons 

sur les plantes. (Paris, 1865.) 

25. Shutt, F. T. .\lkaline Soils of Canada. Can. Exp. Farms Rpt. 

1893, pp. 135-140. 

26. SiGMUND, W. Ueber die Einwirkung chcmischer agenticn auf die 

Kiemung. Landw. versuchst. 47 (1896), No. 2. 

27. SLOS.SON, E. E., and Buffum, B. C. x\lkali Studies, III. Wyo. Sta. 

Bui. 39 (1898), pp. 35-56. 

28. Stewart, J. Effect of .Alkali on Seed Germination. Utah Sta. Rpt. 

1898, pp. xxvi-xxxv. 

29. Tottingham, W. E. .\ Preliminary Study of the Influence of Chlorides 

on the Growth of Certain Agricultural Plants. Jour. Amer. Soc. 
Agr. II (1919), No. I, pp. 1-32. 

30. True, R. H. The Toxic .Action ot Acids and Their Sodium Salts on 

Lupines. Amer. Jour. Sci. 4 ser. 9 (1900), No. 51, pp. 183-192. 
(Abs. E. S. R. 12, p. loio.) 



CHAPTER VI 

NATIVE VEGETATION AS AN INDICATOR OF 
ALKALI 

It is highly desirable that the prospective landowner 
should, by studying the trees, shrubs, and grasses, be able 
to say that the soil is deep, well-drained, fertile, free from 
injurious properties, and capable of producing profitable 
crops. Upon many soils the native plants tend to group 
themselves to the exclusion of nearly all other species. 
Generally when such grouping occurs, there is some pecu- 
liarity of the soil which is made evident by such grouping. 
The luxuriant growth of one species of plant to the exclu- 
sion, or the near exclusion, of other species affords an 
excellent index to the nature of the soil. 

How Plants Indicate the Soil. — Certain plants in arid 
regions are seldom found except when the soil contains 
alkali salts. Davy investigating in California (i) states 
that " there are at least 197 species natives of Cahfornia, 
which are restricted to alkali soils." Some of these plants 
seem to thrive only when some particular salt is present 
in certain strengths, resenting even small quantities of 
other salts. Other plants do well in the presence of any of 
the alkali salts so long as moisture or soil conditions are 
right. In each portion of the arid region may be found 
some plants which indicate extremely large quantities of 
salts when found alone. They indicate that so much alkali 
is present in the soil that the land is worthless for agri- 

60 



HOW PLANTS INDICATE THE SOIL 



61 



cultural plants without reclamation methods lirst being 
applied. 

These characteristic plants are generally recognized by 
the farmers of the district in which they occur, but the exact 
quahties of the soil and the possibilities of its reclamation 
are not so often known. The kind of plant also varies 
considerably even within relatively short distances be- 




tj^p 6t<**>-»gwg*'^- 




Fig. 8. — Alkali Crx'sts at thk Strface I'ri:\i:mtno the 
Growth of Practically all Vegetation. 

cause of difference in soil or drainage. Changes in climate 
or altitude also influence the t>pe of plant that indicates a 
particular type of soil. 

A number of studies of the characteristic plants of alkali 
lands have been made together with the kind and amounts 
of alkali present in soils on which they grew. From these 
studies fairly intelligent conclusions may be drawn as to 
the kind and quantity of alkali in the soil without making 
a chemical analysis. 

In using native vegetation to indicate the alkalinity of 
a soil, however, it is essential that judgment should not be 



62 NATIVE VEGETATION AS AN INDICATOR 

passed when only a few scattered or stunted plants are 
found. Generally when such ' scattered alkah-indicating 
individuals are found the soil contains some alkali, but the 
quantity is not clearly indicated. It is only when the 
plants produce a vigorous growth and occupy the land to 
the exclusion of non-resistant — if not all other species of 
plants — that they may be taken to indicate the kind and 
quantity of alkali characteristic of their species. 




Fig. q. — Alkali Land which is Indicated by the Growth 
OF Shadscale. 

It should be kept in mind also that under certain condi- 
tions alkali-indicating plants may grow well where alkali 
may not be present in quantities injurious to general 
crops and that non-resistant plants may be growing well 
on land so strongly impregnated with alkali that farming 
would be practically impossible without reclamation. 
Such conditions as a shallow hardpan, a dry sandy layer 
of soil, or other conditions which cause the plants to suffer 
for want of water, as they do when in the presence of ex- 
cessive quantities of alkali, may allow the presence of the 
alkali-resistant plants in abundance to the exclusion of 



ALKALI-INDICATING PLANTS 63 

others. On the other luiiul, shallow-rooted ])lants whidi 
cannot endure alkali may grow luxuriantly on land which 
contains alkali below the depth to which its roots feed 
but so near to the surface that when farming is attempted 
the land may soon be ruined. The latter condition is 
represented l)y the Bear River Valley, Utah, where sage 
brush, rabbit brush, and salt grass are growing on land 
practically free from alkali in the upper foot or so, but the 
soil to a depth of six feet contains from 6000 to 30,000 parts 
per million of salts, mostly sodium chloride. This salt is 
quickl}' concentrated near the surface when irrigation is 
practiced, making farming impossible. 

Alkali-indicating Plants. — Some of the characteristic 
plants of the western part of the United States which 
should, when present as a luxuriant growth upon the land, 
be regarded as indicating distinctly alkali soil, or soil 
which should be looked upon with suspicion until chemical 
analyses of it have been made, are given below. 

Well-defined alkali-indicating plants 

Inkweed, or saltwort {Sitacda spp.) 

Tussock grass, or purple top {Sporobolus airoides). Torr. 

Bushy samphire, or Kern greasewood (AUenrolfea occidentalis) (S. Wats.). 

O. Ktze. 
Dwarf samphire {Salicornia spp.) 
Greasewood {Sarcobalus vermiculalns) 

Alkali-heath (Frankenia grandifolia campcnstris). A. Gray 
Sjjike weed {Ilcmizonia pungens) 

Little rabbit brush (bushy goldenrod) {Isocoma veneta) H. R. K. (A. Gray) 
Arrow or irrigation weed {Pluchea servicea) (Nutt.). Coville. (Sometimes 

Piuchea borealis) 
Salt-bush or shadscale {A triplex conferlifolia. etc.) 
Kochia or white sage {Kochia veslita) 
Salt-grass {Distichlis spicata). Greene 
Cressa (Cressa crelica Iruxillensis). Choisy 
Rabbit brush (rayless or false goldenrod) {Cbrysothamnus spp.) 



64 NATIVE VEGETATION AS AN INDICATOR 

Alkali-indicating plants not commonly forming the major 
portion of alkali-land vegetation 

Inhabiting Unoisl saline lands: 
Arrow grass {Triglocliin marilima and T. paliislris) L. (Across continent) 
Alkalimea-dow gTas?,{Puccinclliaairoiclcs. Nutt.) (Entire west. N. Mex.- 

Mont.) 
Marsh grass {Spartina gracilis. Trin.) (Oregon to Texas) 
Trailing buttercup {Hakrpcstcs cymbalaria. Pursh.) (Rocky Mts., n. 

seacoast) 
Shooting star or American cowslip {Dodccalhcon salinmn. Nels.) (Western 

Wyoming, Utah, Idaho) 
Glaux {Glaux maritima. L.) (Suljsaline soil west of ISTississippi) 
Aster {Aster angustus. T. and G.) (Colorado and Utah to Minnesota) 
Aster {Aster pauciflorus. Nutt.) (New Mexico, Arizona, Utah) 
Crepis {Crepis glauca. T. and G.) (West of Missouri to Nevada) 
Plowman's wort {Pluchea camphoraia) (Coast of Florida to Texas) 
Mousetail {Myosurus apelalus. Gay) (Western North America) 
Valeria {Valeriana Jurfurescens. Nels.) (Colorado and Wyoming) 
Pyrrocoma iiniflora. Greene. (Montana to Colorado and Utah) 
Rush {Scirpus nevadensis. Wats.) (Wyoming, California) 
Tuber bubrush {Scirpus pahidosus) 

Inhabiting soil not moist at the surface: 
Bud-brush {Artemisia spinescens. Eat.) (Colorado to Montana and west) 
Aster {Aster zylorhiza. Nutt.) (Southcentral Wyoming. Naked, clayey, 

saline) 
Pyrrocoma lanceolata. Greene (Saskatchewan. Northern Colorado and 

west to Nevada) 
Flaveria angtistifolia. Pers. (Eastern Colorado and New Mexico to 

western Texas) 
Pepper grass {Lepidium montanum. Nutt.) (Montana to New Mexico 

and westward) 
Wild barley {Hordeum nodosum. L.) (Arizona to Alaska) 
Wild rye (£/.vwn(5 5fl//;H/,f. Jones) (Wyoming and Utah. Saline situations) 
Goosefoot or pigweed {Chenopodium rubrum. L.) (Across continent north- 
ward) 
Goosefoot or pigweed {Chenopodium soccosum. Nels.) (Southern Wyoming) 
Monolepsis spp. (Colorado and westward. Saline soils) 

Botanically, probably half of the alkali-loving plants 
belong to the Chenopodiaceae, or goosefoot family, which 



DISCUSSION OI" PLANTS 65 

includes beets, mangles, samphire, saltwort, salt-busli, 
and greasewood. Some of the smaller families such as 
Frankeniaceae, Plumbaginaceae, Rhizophoraceae, and Tama- 
ricaceae are noted for the alkali resistance of most of the 
species. Some other families, notably Cramincac, Cru- 
ciferae, and Compositac, contribute some of the more 
important plants found to do well on alkali lands. 

Discussion of Plants. — " Inkweed, or saltwort, is a 
perennial shrub with a small, fleshy, stem-like leaf. Each 
winter the plant dies down close to the ground leaving 
behind a dark-colored bush" (5). It is found on some 
of the worst alkali lands of California (i), in one in- 
stance being found on soil containing 38,000 parts per 
million of total salt in the top foot of soil, and it has 
been found growing luxuriantly with as high as 32,000 
parts per million of total salts in the top foot of soil. 
Where growing luxuriantly, the soil has been found to 
contain 837 parts per million of sodium carbonate, and 
3313 parts per million of sodium sulphate in the upper 
three feet of soil. It thus indicated a soil with a high 
content of black alkali. Where found in abundance the 
soil is generally of a heavy, sandy-loam or a clay-loam 
texture occurring on low-lying lands and reclaimable only 
at great expense. Because of the presence of black alkali 
the soil is puddled so badly that rainwater generally evapo- 
rates from it before it will penetrate. When found on the 
higher lands, the soil is generally underlain with a hard- 
pan near the surface. 

Tussock grass {S poroholus air aides) sometimes forais a 
coarse, matty or tree-like growth, the trunks of which are 
often from 18 to 20 inches high. It forms feathery purple 
panicles in late summer and is relished by stock better 
than most any other native alkali-resistant plant. Ani- 



66 NATIVE VEGETATION AS AN INDICATOR 

mals eat only the grass part of the plant leaving the trunk- 
like stems behind. It is a good alkali indicator for the 
arid Southwest, but is not common north of the 40th 
parallel, or about the center of Utah and Nevada. It 
has been found growing in a soil with an alkali content 
of 31,190 parts per million in the upper four feet, although 
it makes its best growth with about 3000 parts per million 




Fig. 10. 



Greasewood and Shadscale. These Plants 
Indicate Alkali in the Soil. 



of total salts. Of the separate salts in soil on which the 
plants were growing vigorously, the following amounts 
were found: 

Sodium carbonate 1437 parts per million 

Sodium chloride 387 parts per million 

Sodium sulphate 1227 parts per million 

It has been found growing with over 10,000 parts per 
million of sodium chloride and 20,000 parts per million of 
sodium sulphate. The range of tolerance is great; hence, 
scattered individuals should not be taken to indicate ex- 
cessive quantities of alkali, although when thick and 



DISCUSSION OF PLANTS 67 

vigorous, especially when occurring along with other 
alkali indicators, it may be safe to call the land unsuitable 
for farming. It may occur on dr}- prairie soils where very 
small quantities of alkali are present. 

Kern greasewood or bushy samphire {AUenrolJca occi- 
dentalis) is a shrubby evergreen bush i to 4 feet in height 
with numerous cylindrical, fleshy, practically leafless 
alternating branches, and with a large taproot. It is 
nearly always found on the low-lying, and generally clayey, 
soils with a plentiful supply of moisture. Soils on which 
it does well are usually saturated with water throughout 
the growing season, but may become "dry bogs" during 
part of the year. The salt content of such soils is almost 
invariably high, sometimes reaching over 30,000 (i, 2) 
parts per million of total salts with a good growth of the 
plant. It has been found to make a good growth in the 
presence of 300 parts per million of sodium carbonate, 
13,000 parts per mDlion of sodium chloride, and 17,000 
parts per million of sodium sulphate. It grows with a 
higher sodium chloride content than any other plant known 
at present. Soils on which this plant forms the major 
growth are usually hopelessly alkaline; even salt bushes 
fail on the soils on which Allenrolfea does best. The heavy 
soils make reclamation by drainage difficult so that such 
soils can seldom be used profitably. 

Dwarf samphire {Salicornia suhterminalis and other 
species) is a nearly leafless plant with cylindrical, fleshy, 
many-jointed, opposite branches. All soils upon which it 
has been found are excessively alkaline. It grows well 
on land with a total salt content of 27,000 (i, 2) parts 
per million in the upper four feet. Analyses of the soil 
on which it was growing well showed it to contain 757 
parts per million of sodium carbonate, 7852 parts per mil- 



68 NATIVE VEGETATION AS AN INDICATOR 

lion of sodium chloride, and 19,627 parts per million of 
sodium sulphate. Thus, it resists larger quantities of 
sodium chloride and sodium sulphate than most other 
plants. Both the seashore and the inland species indicate 
land which is useless for farming until reclaimed by pro- 
longed draining, which in many cases is at present un- 
economical. 

Greasewood {Sarcohatus vermiculatus) is one of the most 
common alkali-indicating plants found on moist saline 




Fig. II. — The Border between Greasewood and Salt Grass. 
The Land Increases in Alkali toward the Salt Grass. 

fiats of the intermountain country. Viewed at a distance 
the patches of greasewood have a pleasant bright-green 
color decidedly in contrast to much of the darker or gray- 
ish alkali vegetation. Besides the numerous sharp spines 
which protect the small fleshy leaves from browsing ani- 
mals, the plant is bitter and salty so that no useful animal 
will eat it. Although it has not been found on soil con- 
taining more than 8000 (4) parts per million of total salts 
in the upper feet, its large taproot has been found pene- 
trating soil with nearly double this amount of salt (mostly 



DISCUSSION OF PLANTS 69 

sodium chloride). Hilgard (2) reports 1170 parts per 
million of sodium carbonate, 230 parts per million of 
sodium chloride, and 2260 parts per million of sodium 
sulphate as being characteristic quantities of the common 
alkali salts present where the plant does best and that its 
presence "invariably indicates a heavy impregnation of 
land with black alkali or carbonate of soda" (2, page 542). 
Although the latter statement is generally true, it has 
been found on land showing only sulphates, and Kearney 
and others (4) found it growing on land in Utah without 
sodium carbonate as a chaiacteristic salt. Kearney says 
it is not an infallible alkali indicator as it w^as found makinir 
its largest and thriftiest growth on dunes of pure sand. 
It is usually associated with a rich silty or sandy soil, 
moist in the upper foot and containing excessive quantities 
of salts. It will endure larger quantities of alkali than 
most alkali plants. Greasewood soils are sometimes too 
alkaline to permit profitable reclamation. 

Alkali-heath {Frankenia grandijolia campcnstris) is a 
perennial herb with opposite or clustered simple leaves 
and with a deep-rooted, flexible, wiry, rootstock. It is a 
hardy plant which often persists as a weed on cultivated 
land. Although it generally indicates strong alkali where 
it is growing luxuriantly, it will grow with a great varia- 
tion in alkali content — from about 200 to 31,000 (i, 2) 
parts per million of total salts. The optimum quantities 
found by Hilgard (2) ranged from about 4000 to 17,600 
parts per million in the upper four feet of soil. Of this 
amount 43 to 1224 parts per million was sodium carbonate, 
360 to 636 parts per million sodium chloride, and 2158 to 
17,220 parts per million sodium sulphate. Hilgard re- 
gards land that grows this plant to be unlit for crops with- 
out reclamation, although Mackie (5) says it will generally 



70 NATIVE VEGETATION AS AN INDICATOR 

contain comparatively small quantities of alkali, and 
where this bush is found growing uniformly over an area 
to the exclusion of the most resistant alkali indicators, 
the alkali is found below the surface from i to 3 feet in a 
free sand or sandy loam soil. This " land yields crops " of 
alfalfa and grain or orchards and can be kept free from 
injurious quantities of alkali by proper methods of irriga- 
tion and drainage." 

Cressa {Cressa cretica iruxillensis) is a perennial herb 
with a woody base from which many leafy branches ex- 
tend. The leaves are almost sessile and are characterized 
by their silky, villous, and hairy nature. Cressa is a com- 
mon sea-coast plant in many of the arid parts of the world. 
In the United States it is found along the Texas coast 
and scattered throughout California, extending at least 
to the Arizona line. Alkali-heath has been found growing 
with a higher total salt content than Cressa, but Cressa is 
a surer indicator of irreclaimable alkali land because the 
lower limit in which it grows is much higher. Although 
sulphates predominate in Cressa soil, it will be noticed 
that it does well with chlorides in quantities dangerous 
to ordinary crops. 

Salt-bush, or Shadscale {A triplex spp.), is of two types — 
the perennial, which is generally bushy or shrubby, and 
the type that occurs as an annual weed. The leaves are 
usually alternate, simple, and often silvery, scurfy, or 
having an ashen-gray color, the bush type often being 
mistaken for sagebrush. The bush belongs to the same 
family as the beet and it can readily be detected by its 
beet-like seeds. A number of the A triplex species grow 
in soil which contains little or no alkali, but the moisture 
conditions are generally unfavorable on any soil which 
has a vigorous growth of them, and most of the common 



DISCUSSION OF PLANTS 



71 



species of the western arid country produce their most 
luxuriant growth in the presence of dangerous quantities 
of alkali. Land upon which saltbush — either bush or 
weed — grows best is generally light and free from alkali 
in the top foot or so, but is underlain by heavier soil which 
is likely to contain large quantities of alkali. Such soils 
are seldom underlain by hardpan and are usually porous 




■The L.\sr 1'laxt to Auwixix an Alkali Flat 



SO that they may be reclaimed by flooding. Crops can as 
a rule be grown on the soil on which saltbush occurs, but 
there is likely to be a rise of alkali where great care is not 
taken to prevent it. The alkali is likely to be of the white 
type entirely, although it will grow with as much as 1200 
parts per million (2) sodium carbonate in the soil. The 
annual A triplexes are similar to the bushes in color and 
appearance of the leaves but do not have the persistent 
woody base of the latter. They range in height from 
about I to 4 feet. Land upon which A triplex forms the 
principal vegetation should be looked upon with suspicion 



72 NATIVE VEGETATION AS AN INDICATOR 

until borings and analyses show it to be free from alkali, 
unless plans are laid for immediate drainage. Soils con- 
taining as much as 10,000 parts per million (3) of salts — 
mostly sodium chloride — but with the upper foot or so 
dry and free from alkali, have been found to produce 
excellent saltbushes. They grow equally well in the 
presence of nearly 8000 parts per million (2) of sodium 
sulphate. Because of the porous, dry, upper soil, and the 
tendency to have alkali beneath, such soils are ordinarily 
unfit for dry-farming. 

KocJiia, or White Sage ( Kochia hestita) , is a low-lying 
shrub with its branches close .to the ground and with a 
strong taproot which, however, seldom penetrates to a 
greater depth than one foot. New shoots are sent up from 
its roots. Its leaves are alternate, sessile, villous, narrow, 
and entire. The branches as well as the leaves are fre- 
quently covered with short woolly hairs. It is found in the 
intermountain country from Colorado to Nevada. Land 
upon which it occurs is usually free from injurious salts 
in the upper foot or so, some observations showing the 
upper foot to contain about 1200 parts per million of total 
salts (4) , but the soil beneath which its roots feed is almost 
invariably impregnated with so much alkali that deeper 
rooting plants, such as the sagebrush {Artemesia tridentata) 
cannot exist. Kochia itself is not alkali resistant, but 
where it exists to the exclusion of sagebrush and similar 
nonresistant plants the lower depths of soil are either 
high in alkali or underlain at shallow depths with a hardpan 
which prevents deep penetration of roots. Either con- 
dition makes the land undesirable for general farming be- 
cause of the likelihood of a rise of alkah. Kochia land 
frequently contains some black alkali and the soil is often 
rather impervious so that reclamation is difficult. 



OTHER PLANTS 73 

Salt-grass {DislicJilis spicala) occurs throughout the 
world, being the most common plant found on alkali lands. 
It grows well on land so free from alkali that some of the 
common alkali- loving plants such as grease wood fail, but 
can withstand and make a good growth with as much as 
24,000 parts per million of total salts in the soil. No 
preference is shown for any of the alkali salts. The high- 
est quantities found in soil on which it grew well are as 
follows : 

Sodium carbonate 8517 parts per million 

Sodium chloride 4398 parts per million 

Sodium sulphate 2750 parts per million 

These quantities are only suggestive, however, as great 
variations are found wherever the grass is found. It is 
a poor indicator of alkali either quantitatively or quali- 
tatively, but when taken together with other plants grow- 
ing with it something of the nature of the land may be 
indicated. 

Other Plants. — A number of other plants which do 
well on alkali soils, but which are not so distinctive as a 
general rule, are the following: Rabbit brush or false 
golden-rod {Chrysothamnus spp.) which is cluster-flowered 
and woody-based; Plowman's wort {Pluchea camphorata 
(i) DC), a spicy or salt march Fleabane found in the 
marshes of Texas and Mexico as well as on the eastern 
and southern coast of the United States; little rabbit 
brush {Isocoma veneta Grey) a perennial composite bush 
about 18 inches high with a sparse, smooth, dark-green 
foliage usually growing in deep loamy soils with a medium 
salt content; spike weed {Hemizonia pungcns), a yellow- 
flowered spiny composite which grows in a dense mass 
to the exclusion of most other plants on comparatively 
weak alkali land with fair drainage; arrow or irrigation 



74 NATIVE VEGETATION AS AN INDICATOR 

weed {Pleuchea borealis), a composite with a brush-like 
head supported on a stem 4 to 8 feet high wliich tolerates 
a limited quantity of alkali on a porous, deep, well-drained 
soil. Plants other than those discussed above are char- 
acteristic of alkali lands in their respective districts, but 
sufhcient data are not at hand to determine their exact 
reliability as to alkali resistance. Many other plants 




Fig. 13. — Plants Growing at the Top of Sand Dunes, the Only 
Place where the Alkali is not too Strong for plant Growth. 

grow upon alkali land during the wet season when the soil 
solution is dilute, but none of them can be classified as 
distinctive in determining soil alkali conditions. 

Description of Alkali-indicating Plants. — AllenroJJca 
occidentalis {Watson) Kinitzc. — Bushy samphire or kern 
greasewood is a shrubby evergreen bush i to 4 feet high 
with numerous cylindrical, jointed, fleshy, practically leaf- 
less alternating branches. The leaves are triangular or 
scale-like in shape. It has a large taproot and but few 
lateral roots. Generally found in low-lying moist lands 
from the 40th parallel southward, the northern plants 



DESCRIPTION OF ALKALI IXDICAILXO I'LAXTS 75 

generally being somewhat more dwarfed than those farther 
southward. 

Aricmcsia spincsccns {Eat). — Bud brush has the woolly 
covering and the general appearance of common sagebrush, 
but is dwarfed — 4 to 16 inches high — and is spiny. 
Found throughout the West. 

Aslcr angustus. — Perennial herb with stems 4 to 12 
inches high, branching, leafy. It has the typical aster 
design of flowers, but they are smaller with the corolla 
of the ray flowers reduced to the tube and much shorter 
than the elongated style. 

Aster paucijiorus. — Stems 8 to 10 inches liigh from a 
slender root-stock, single and bearing few heads. Leaves 
moderately fleshy and elongated in shape. 

Aslcr xylorliiza. — Perennial with deep-set woody roots 
supporting several or solitary stems. The heads are large 
with conspicuous white rays. Stems leafy, about 4 to 8 
inches high, terminating in a short flower stalk. 

A triplex. — Salt-bush or shadscale {A triplex spp.), peren- 
nial and annual t^pes — perennial usually bushy or 
shrubby, and annual usually taller and more weed-like. 
Lea\'es generally alternate, simple, and often silvery or 
white scurfy or having an ashen-gray color. Bush is 
often mistaken for sagebrush, but several species have 
spines or thorns. 

Crcpis glauca. — Perennial herb with few small }-ellow 
flowers borne upon a leafless or practically leafless long 
stem. It is from 8 to 24 inches high and characterized 
by its covering of white powdery material on leaves and 
elsew'here and lack of pubescence. 

Chrysothamnus spp. - - Rabbit brush, or false golden-rod, 
are shrubby plants v.ith woody base on which shoots 
holding cylindrical, often hairy, but sometimes resinous 



76 NATIVE VEGETATION AS AN INDICATOR 

leaves, are found. Clusters of yellowish flowers like those 
of golden-rod but lacking the ray-flowers around the margin 
of the clusters as in the golden-rod. The most notable 
alkali-loving species of this group is Chrysotliamnus lini- 
folius, which is found along wet banks of alkali streams; 
C. Wyomingesis and C. plattcnsis are found more on alkali 
plains. 

Cressa truxillensis. — A perennial herb with a woody 
base from which many leafy branches extend. The leaves 
are oblong or lance-shaped with very short stems, silky, 
hoary, or villous covering. It is found mostly near the 
seashore in Texas, but in California is found inland through- 
out the state, 

Distichlis spicata. — ■ Salt grass is the common salt 
grass of alkali soils. 

Dodccatheo7i salinum. — Shooting star or American cow- 
slip has a short crown from which spring numerous slender 
matted roots. Leaves about i inch in length, wide-spread- 
ing or ascending, smooth, and rather elliptic. Flowers 
borne upon a stem about 4 to 8 inches long are of a yel- 
lowish white with an indistinct purplish ring near the 
base and has segments of lilac-purple in places. 

Elymiis salinus {Jones) . ■ — Wild rye is a coarse perennial 
grass with flat rough leaves. It forms in dense bunches 
of rigid, wiry grass standing from i to 2 feet high. Found 
in Utah and Wyoming frequently in saline places. 

Flaveria angnstifolia. — This is a smooth-appearing 
herb with clusters of yellowish flowers and opposite stem- 
less leaves. It is 8 to 20 inches in height. 

Frankenia grandifoUa. — Alkali-heath is a perennial 
herb with a woody base and deep-rooted flexible, wiry, 
root-stocks. Numerous opposite or clustered simple rather 
thick, lance-shaped leaves from 3 to 6 inches long. Largely 



DESCRIPTION OF ALKALI-INDICATING PLANTS 77 

confined to the Southwest as far north as Arizona and 
southern Nevada. 

Glaux marilima. — A salt marsh, small leafy-stemmed 
perennial herb propagated by slender running root-stocks. 
Stems about 2 to 4 inches high. Leaves oval-shaped. 
Flowers purplish or white. 

Halerpestes cymhalaria. — Trailing buttercup is so named 
because of long-jointed stolons from which spring new 
plants at each node. Low-growing, rather hairy, with 
yellow flowers and oblong cylindrical heads of fruit; found 
in moist places. Leaves broadly egg-shaped, coarsely 
toothed and clustered at the base of the flower stems or 
nodes of the stolons. Flower stem 2 to 4 inches high. 

Hemizonia pungens. — Spike-weed is a yellow-flowered 
much-branched spiny composite from a few inches to 2 
or 3 feet high. The leaves are arranged opposite along 
hairy or bristly branches. Found in dense patches fre- 
quently to the exclusion of other plants on well-drained 
generally mildly alkali lands of southern California. 

Hordeum nodosum (L.). — Wild barley, sometimes called 
foxtail, belongs to the same group as common barley, but 
is seldom taller than 24 inches. Has a narrow spike which 
is usually dark green or purple, and is awnless. 

KocJiia. — White sage {Kochia vestita), dull gray plant 
about 5 to 6 inches high with a shrubby base and roundish 
densely hairy leaves. Viewed at a distance, bunches give 
appearance of gray blanket. Flowers solitary or few in 
the axils. Ovary oblong nearly equaling the calyx. 
Ripened ovary membranous. Strong taproot to about i 
foot deep. 

Lepidium montanum ( Nutt). — Pepper grass is a smooth 
appearing biennial herb with small white petals. The 
stems spring from the crown of the thick root and extend 



78 NATIVE VEGETATION AS AN INDICATOR 

to a distance of 4 to 8 inches from the base. The leaves 
are toothed or have numerous leaflets along the main axis 
of the leaf. 

Myosurus apetalus {Gay) . — Mousetail is a very small 
annual herb with a tuft of spatulate entire leaves, with no 
apparent stem, surrounding a simple solitary live-petaled 
flower borne on a stem i to 2 inches high. It is found in 
wet saline places throughout the western states. 

Pluchea horealis. — Arrow, or irrigation, weed is a com- 
posite with a brushlike head supported on numerous 
hairy-covered, silvery, willow-like branches 4 to 8 inches 
high. Common along sandy or porous, deep, well-drained 
banks of streams or similar soils elsewhere. 

Pluchea camphor ata {L) DC. — Plowman's wort is a 
spicy, or salt marsh, Fleabane found in the marshes of 
Texas and Mexico. 

Pyrrocoma ( Null) . — Perennial herbs with alternate 
leaves and showy many-flowered heads of yellow flowers 
in the axils of the upper leaves or at the end of the branch. 
Plants generally from 4 to 8 inches high. Found through- 
out the Rocky Mountains. 

Salicornia spp. — Dwarf samphire is a low scaly-leafed 
but nearly leafless fleshy plant with cylindrical, many- 
jointed stems, and opposite branches. Frequent on 
saline land near lakes and ponds. 

Sarcohatus vermiculatiis. — Greasewood of inter- 
mountain country found on moist saline flats, patches of 
which generally appear a much brighter green than most 
saline vegetation except in fall when it changes to a yel- 
lowish color. Il» has numerous sharp spines at the base 
of which are small fleshy leaves with a bitter salty taste. 
It is a rigidly branched shrub about 2 to 8 feet high with a 
smooth whitish bark. 



DESCRIPTION OF ALKALI-INDICATING PLANTS 79 

Scirpus spp. — Ruslics arc tufted plants with creeping 
root-stocks, the stem sheathed or leafy at the base and the 
spikelets in lateral cluster. Saline soils growing these plants 
are generally irreclaimable without considerable expense. 

Spartina gracilis. — Marsh grass is a perennial with 
simple and rigid slender reed-like stems coming from ex- 
tensively creeping scaly root-stocks. Stems generally 
8 to 23 inches high and somewhat taller than the spreading, 
two-ranked, rough, and rigid leaves at its base. Spikes 
4 to 10, mostly sessile, closely appressed to the nearly 
smooth rachis. 

Sporoholus airoides. — Tussock or dropseed, or purple 
top grass, has a stout coarse and rigid base or trunk often 
18 to 20 inches high. The tufts of grass are often i to 3 
feet in height. Open, feathery, pyramidal panicles with 
a purplish tinge in late summer are borne from the base 
trunk. Leaves smooth beneath but harsh above and taper 
gradually from base to a fine point somewhat rolled in- 
wardly at the end. 

Suaeda spp. — Inkweed, or saltwort, perennial shrub, 
with small, fleshy, stem-like leaves. Growing plants 
generally i to 2 feet in height but the dark-colored brush 
left when the plant ceases growth in the winter lies close 
to the surface of the ground. 

Triglochin maritima. — Arrow grass gives the appear- 
ance of an arrow because of a naked jointless stem bearing 
an arrowhead shaped greenish flower and having cylindri- 
cal rush-like leaves at the base which are shorter than the 
flower stem. About i to 3 feet in height and rather stout 
appearing. T. palustris similar to above but seldom 
reaches a height greater than i foot and the basal leaves 
are narrower than 2 mm., while leaves of above are from 
2 to 4 mm. wide. 



80 NATIVE VEGETATION AS AN INDICATOR 

Valeriana Jurjurescens {Nds.). — -The roots of this 
plant are slender and peculiarly scented, leaves entire, 
flowers minute and numerous with greem'sh yellow corolla. 
Fruit hairless, rough, and scaly. Found mostly in saline 
meadow lands. 

REFERENCES 

1. Davy, J. B. Investigations on the Native Vegetation of Alkali Land;-. 

Cal. Sta. Rpt. 1895-97, pp. 53-75. 

2. HiLGARD, E. W. Soils, pp. 527-549. (New York, 1906.) 

3. Jensen, C. A., and Strahorn, A. T. Soil Survey of the Bear River 

Area, Utah. U. S. D. A. Bur. Soils, Field Oper. 1904, p. 27. 

4. Kearney, T. H., Briggs, L. J., Shantz, H. L., McLane, J. W., and 

PiEMERSEL, R. L. Indicator Significance of Native Vegetation in 
Tooele Valley, Utah. Jour. Agr. Res. Vol. i (1914), pp. 365-417. 

5. Mackie, W. W. Reclamation of White-ash Lands Affected with Alkali 

at Fresno, California. U. S. D. A. Bur. Soils, Bui. 42 (1907), pp. 45- 

47- 

6. Myers, H. C. Alkali Lands and Sugar-beet Culture. Jour. Soc. 

Chem. Ind. 22 (1903), pp. 782-785. 
Also consult standard books on Botany. 



CHAPTER VII 

CHEMICAL METHODS OF DETERMINING 
ALKALI 

TiiJiRE are so many distinctly different methcxis of 
making chemical analyses of soils that it is \ery difficult 
, to compare the work of the various investigators who have 
studied alkali under field conditions. The wide variations 
so often noted between results of investigators in different 
places may be accounted for in part by the differences in 
methods of determining the quantity of alkali present. 
It is necessary that the method used be known before in- 
telligent interpretation of analyses can be made. In the 
interest of uniformity it would be highly desirable to adopt 
standard methods. Before this can be done, it will be 
necessary to make a careful study of the various methods 
in order that the best one to secure uniformly accurate 
results may be chosen. 

Preparing the Solution. — Probably the greatest varia- 
tion in methods of analyzing alkali soil is found in making 
the soil extract. The soluble salts are dissolved with water 
and not with the stronger dissolving agents that are used 
in making a complete analysis of a soil, since it is the 
water-soluble salts that come under the designation of 
alkali. The principal variation in methods consists in 
the relative quantities of water and soil used, the time of 
agitation, the time allowed for settling, and the method of 
filtering. There are certain other methods, such as ex- 

8i 



82 METHODS OF DETERMINING ALKALI 

trading the solutions with oil or by pressure or centrif- 
ugal force, which are not in general use as yet, the great 
drawback being that little more than the free water can 
be obtained. 

King and his associates in their studies of soil nitrates 
used a method which, with a number of amendments, has 
been used extensively by later investigators, Schreiner 
and Failyer (9) describe a modification of this method 
which has probably been used more widely than any other. 
They discuss it as follows: 

"If comparable results are to be obtained, it is essential 
in preparing the soil extract to follow as nearly as practical* 
a uniform procedure. The volume of water used and the 
time of its action are necessarily conventional. The ratio 
of five parts of water to one part of soil has been adopted 
in procuring solutions of the readily water-soluble salts 
in many of the soil studies. The mixture is agitated three 
minutes and allowed to stand twenty minutes before 
filtering. The exact procedure when the soil to be ex- 
amined is still in the moist state as collected in the field 
varies slightly from that when it is air-dried or oven- 
dried. All results, however, are stated on a uniform basis, 
preferably on the dry soil. The results from a moist soil 
are not comparable with those obtained from a dried soil, 
although both be stated in terms of dry soil, owing to the 
fact that dried soils give a somewhat greater concentra- 
tion of soluble salts in the soil extract. 

"From Moist SoiL — The moist samples taken from 
typical and comparable portions of the field are well broken 
up and mixed in a granite- ware basin or porcelain dish. 
Two 100-gram portions of this composite are then weighed 
out on a balance capable of weighing accurately to within 
0.1 gram. One of these portions is for the moisture de- 



FROM MOIST SOIL 83 

termination. It is thorough I}- chicd in an o\cn and the 
content of moisture thus obtained taken into consideration, 
if the results of the analyses of the solution are to be ex- 
pressed in terms of the dry soil. The calculation to parts 
per million of dry soil is readily made by means of the 
following formula: 

5(500 + W) 



s = 



(100 - W)' 



where S is the parts per million of the dry soil, 5 the parts 
per million of the soil solution as found by analysis, and 
W is the amount of moisture in grams, in the 100 grams 
of the moist soil sample used in making the solution as 
described below. If it should be desired to calculate the 
strength in parts per million of the actual soil moisture as 
found in the above moisture determination, the following 
formula is applied: 

5(500 -f W) 



M = 



W 



where M is the parts per million of the soil moisture, 5 and 
W as in the previous formula. 

"Measure out 500 cc. of water, and after transferring 
the other 100-gram portion of the moist soil to a mortar 
add enough of the water to make a thick paste, working 
well with the pestle so as to break down all granulations 
and to have the soil well puddled. The balance of the 
500 cc. of water is then added and the mixture well stirred 
with the pestle during three minutes. If more samples 
are to be worked in the mortar, the mixture is transferred 
to a jar and is allowed to stand twenty minutes, during 
which the coarser particles settle. The supernatant 
turbid liquid is then poured into one of the filtering cham- 



84 METHODS OF DETERMINING ALKALI 

bers fitted up with a well-washed Pasteur-Chamberland 
filter tube. 

*' From Dry Soil. — If the soil sample to be used is al- 
ready air-dry and it is desired to give the results in terms 
of the completely dried soil, it will be necessary to de- 
termine the amount of moisture still present by heating 
a loo-gram portion in the drying oven and making the 
proper allowance in the final calculation, using the formula 
given above. If the soil to be examined is oven-dried 
the whole composite is removed from the oven while hot 
and pulverized in a large mortar, screening through a 
2-mm. seive. A loo-gram sample is then weighed out 
and poured into a glass-stoppered bottle. Add 500 cc. 
of distilled water to the soil in the bottle and shake vigor- 
ously for three minutes to insure a thorough puddling of 
the soil particles. The mixture is allowed to stand twenty 
minutes for the coarser particles to subside and is then 
filtered. The mortar may be used as described above, 
but it is more convenient to use the shaking bottle when 
working with dry pulverulent soils." 

Methods differing from the above for extracting soil 
solutions, as summarized by Hare (7) are: the Arizona 
method in which 50 grams of soil are added to 8oo cc. 
of water and heated on a water bath for 10 hours when 
enough water is added to make the solution up to 1000 cc. 
and the solution allowed to stand over night before being 
filtered; the California method in which 150 grams of soil 
are added to 300 cc. of water and after shaking allowed to 
stand 12 hours; the Montana method in which 50 grams 
of soil are added to 500 cc. of water, shaken and allowed 
to stand over night; the Texas method in which 200 grams 
of soil are added to 1000 parts of water and shaken oc- 
casionally for 2 hours; and the Utah methods, in the 



COMPARISON OF RESULTS 



85 





Ti"^ 


O 1- o 


CO 


-t 


M 


NO p t-5 




c o 


M n lo 


o 


o 


1^ 


Tt- CO NO O 




,^ c_; 


00 M ro 


fs 


o 


o 




^.a y, 










• in 




.— 4j 










t -~^ a 




<S 








o 


U 




c g's 


T)- 0> 'o 


,^ 


o 


o 


[^ t^ 




OJ C _c 














Perc 

of 

Arizfi 

Metl 


t^ M ri 


>n 


d 


-+ 


-^ CO • 




1^ O^ w 


"-> 


o 


M 


On 0> 




'-' 




M 


•^ 






■V 










M O - i 




-= 2 


r. T^ <* 


NO 


-^ 


M 


ON O c-j 








M 


8 


00 

o 


M CO O 












"* 




Jr cent 

of 
rizona 
lethod 1 


>0 N CO 
M O d 


lO 


o 
o 




■* 

t^ lO 




I^ OO CO 


't 


o 




t^ o- 




6 <-* 






M 








few 1 
exico 
:thod 


-J- l^ <V5 


't 


'i- 




On •+ 




CO O CO 


On 


o 




n 




U-) M cs 


o 


o 




■+ CO 




^^^ 










CO 




C CO 


O <r) 


NO 


o 




lO iH 




S^ Oj= 


00 6 • 


ri 


o 




CO <^l 




It, ^^ 


KQ ON 


ro 


o 




CO On 




so 


lO Ol 


00 


"t 




^ "^ 




/^ 2^ 


LO PI -^ 


NO 


o 




On o> ,^ 




Cl StJ 


lO H-t 'T 


o 


o 


lO 


NO (N ^ 




Hjs 










CO ' '~^ 




1 il 


M 




o 




!>• CO 




l^'o|'^ 


O ^ ^ 


ro 


d 








(li <s 


^0 


o 




00 On 




^"^■^ 


CO >0 w 


On 


Tt 




M On rrj 
NO c^ -^ 




O ro O 


IN O PJ 


NO 

o 


o 
o 


(N 




U 3 iJ 














^£S 










CO 




:r cent 

of 
rizona 
lethod 


lo O •* 


NO 


o 


NO 


On O 




r^ t^ ro 


^o 


o 


J^ 


CO O 




\0 00 t^ 


CO 


o 


NO 


00 On 




^ <-* 






tH 








i 2 


lO O «o 


o 


o 


CO 


lO 00 CO 

M 00 M 




o>i; 


lO M « 


o 


o 


o 


t>» c< o 












CO 




g S"? 


O t^ t^ 


M 


o 


CO 


ON '^ 




S-3|-S 


»o O lo 


M 


d 


M 


r^ 00 






O On O 


O 


o 


CO 


O CO 




£ <S 






" 








.4 

ali- 
rnia 
:thod 


►H (N O 


NO 


^ 


CO 


00 CO t-~ 




ro w ro 


't 


o 


o« 


s °° ^ 




lO M O) 


o 


o 


o 


O cs O 




U o^ 














^^ 










CO 




_ . 


00 


ON 








o 






■= ° 


to 




lO 








NO 






M 




N 








ri 








>o 




lO 








IT) 








tH . - 


t/3 


u ■ - 




t/) 




>H 


t« . 






4J 

a 












rt 


c 
aj 




y 


1) 




c 




z 


u 




;?; 






o 




1 


o 




.0 
c 


■h 




^1. 








>, 


OJ 


r2 








'e 


"o 




"o 


, 


*J •-< 


- 


"o 






Ul 


S s5c5 


t« 




c c 


6 


CAl 


s sio" 




4; 


^■O G — U 


*^'2 


o — < 


u 


^:2 o — u 




a 


3 sl ^J^J" 


-3 c"S 


iH rt 


d 


—; C !- "-1 rt c^ 




rt S o 

o ^2 


a=^ 


z 


rt <u O Ji^ ►^ 
o " S O.- -^ 






H 


u 


< 


H 


U 




< 




H 


u 


< II 



o 
u 



o 
u 



lO 1-1 r*-. 



;<5 



86 METHODS OF DETERMINING ALKALI 

first of which 50 grams of soil are added to 500 cc. of water 
and in one case agitated for 5 minutes, and in the other 
case shaken intermittently for 24 hours, while in the 
second method 50 grams of soil are added to 1000 parts 
of water and after shaking for 8 hours allowed to stand over 
night. 

From comparisons of methods at the Utah Station, the 
proportion of soil to water influenced the quantity of 
carbonate found, but had little or no influence on chlorides 
or sulphates. 

After the solution has been in contact with the soil 
for the desired length of time, it is poured into a Pasteur- 
Chamberland filter and filtered under an air pressure of 
30 to 40 pounds per square inch. The first 50 to 200 cc. 
of the filtered solution are discarded, after which the desired 
quantity is collected and bottled until needed for making 
the tests of the different constituents. 

Determining Total Solids. — The ordinary method of 
determining the total soluble salts in the extracted solu- 
tions is to evaporate 20 to 50 cc. of the solution to dryness 
in a weighed evaporating dish over a sand or steam bath. 
Some chemists gently ignite the residue further to purify 
the salts of undesirable material, while some re-dissolve 
the residue to get the soluble alkali salts and help eHminate 
calcium and magnesium salts. The Bureau of Soils does 
not determine the total salts by evaporation and declares 
it to be unreliable. 

In Table XI is shown the total salts and the various 
constituents of alkali as determined by the different 
methods on alkali soils in Arizona (12). 

Carbonate and Bicarbonate Determination. — The 
method for determining the carbonate and bicarbonate 
used by the Bureau of Soils (9) is described as follows: 



CARBONATES AND BICARBONATES 87 

"One portion of the solution will serve for the determina- 
tion of both carbonate and bicarbonate. The method 
depends upon the different actions of phenolphthalein 
and methyl orange in the neutralization of these two 
substances. Potassium hydrogen sulphate solution is 
used for titrating, the first step being the phenolphthalein 
as indicator. The reaction is expressed by the following 
equation : 

Na2C03 + KHSO4 = KNaS04 + NaHCOg. 

The point of neutrality is shown when all carbonate present 
is converted into bicarbonate. The second step is the 
titration of the bicarbonate formed in the first step to- 
gether with that existing originally in the solution, using 
methyl orange as indicator. This reaction is expressed 
by the following equation: 

NaHCOa -f- KHSO4 = KNaS04 + H2CO3. 

The point of neutrahty is shown in this case when all 
bicarbonate has been decomposed." The total titration 
for bicarbonate, less the titration for the carbonate, gives 
the titration for the bicarbonate originally present. 

This and certain other methods for determining car- 
bonates does not always prove satisfactory as it does not 
distinguish between the sodium and the noninjurious 
calcium and magnesium salts. 

The New Mexico Station uses the above method for 
determining the carbonates, but also determines the 
calcium and magnesium and combines these bases with 
carbonates before determining the sodium salts of the 
carbonate radical. With the exception that sulphuric 
acid is used in the place of potassium acid sulphate and 
that methyl orange is the indicator, this is also one of the 
methods used in Utah. 



88 METHODS OF DETERMINING ALKALI 

In the work at California no distinction has been made 
between the carbonate and the bicarbonate of soda. Their 
method of first evaporating the solution, then igniting 
the residue, and finally redissolving the salts before 
titrating with sulphuric acid, using methyl orange as the 
indicator, eliminates most of the calcium and magnesium. 
After this the solution is titrated with sulphuric acid, and 
the difference between the sodium carbonate added and 
that indicated by the titration shows the sodium carbon- 
ate present originally. If there is a deficit, the quantity 
of calcium and magnesium carbonate in excess is shown. 

Acting on the assumption that all carbonates and bi- 
carbonates were combined with sodium when in the soil, 
the Utah Station titrates the original solution with sul- 
phuric acid and states the results as sodium carbonate. 
Where the solution remains in contact with the soil but 
a few minutes, it is assumed that the less soluble lime and 
magnesium salts will be present to only a slight extent, 
but where the agitation is continued for long the results 
are high compared with other methods on account of the 
presence of carbonate other than those of sodium. 

Chloride Determination. — The method used in prac- 
tically all places for determining chloride is to titrate lo 
to 50 cc. of the original solution with standard silver 
nitrate solution, using potassium chromate as the indicator. 
The results are expressed as the sodium salt. As shown 
in Table XI, the results by the different methods are 
fairly uniform, although by heating to get the solution, 
as is done by the Arizona method, the results are some- 
what higher in most cases than with the other methods. 
An excess of silver nitrate titrated back with ammonium 
sulfocyanide is sometimes used, but it is rather hard to 
read in brown solutions. The turbidity method for 
chlorides is little used. 



NITRATE DETERMINATION 89 

Sulphate Determination. The most common method 
in use for determining suli)hcites is to acidify the solution 
with a few drops of hydrochloric acid and after bringing 
the solution to boiling, to add a few cubic centimeters of 
boiUng standard barium chloride. The solution is kept 
boihng for about an hour and then filtered through an 
ordinary filter paper and the precipitate thoroughly washed 
with hot water. The precipitate and the filter paper are 
then placed in a weighed cruciljle which is heated until 
all volatile matter is driven off. After this the crucible is 
reweighed and the difTerence as barium sulphate calculated 
first to calcium and magnesium and the remainder to 
sodium, if the former bases have been determined, but 
otherwise the sulphates are all expressed as sodium 
sulphate. 

Turbidity and colorimetric methods for sulphate de- 
termination have been employed to a slight extent, but 
they are not in common use. In certain places, notably 
at the Cahfornia Station, the difference between the total 
solids and the sum of the carbonates and the chlorides 
has been expressed as sodium sulphate. As the sulphates 
are least harmful, and in certain localities seldom present 
in injurious quantities, they are frequently omitted from 
analyses of alkali. 

Nitrate Determination. — Nitrates are seldom deter- 
mined in alkali investigations, but under a few conditions 
such as prevail in parts of Colorado and Utah, they reach 
toxic concentrations, and it is therefore desirable that the 
quantity present be known. The method for nitrate de- 
termination, which has been most extensively used in the 
past, is discussed by Schreiner and Failyer (9) as follows: 

"The nitrates are best determined by means of the 
color produced by the action of phenoldisulphonic acid 



90 METHODS OF DETERMINING ALKALI 

and making alkaline with ammonia. Chlorides, when 
present in considerable quantities, interfere quite markedly 
with the determination of nitrates and must be previously- 
removed. This is best accomplished by means of silver 
sulphate free from nitrates. This can be added in the 
solid form, thus avoiding dilution of the original solution. 
The silver sulphate is tested for nitrates by treating some 
of the solid salt with the phenoldisulphonic acid reagent, 
diluting with water and adding ammonia water. No 
yellow color should be produced. The silver sulphate as 
found in the market frequently contains nitrates in amounts 
sufficient to vitiate all results, and it is, therefore, advis- 
able to prepare it specially for this work. 

"The presence of some kinds of organic matter also in- 
terferes seriously with the determination of nitrates by 
this method. In some cases it is the foreign color only 
which is produced by the strong acid, but often the action 
is of more vital importance, as a considerable loss of nitrates 
occurs, possibly due to oxidation of the organic matter 
by the nitrate instead of the nitration of the phenoldisul- 
phonic acid. In some cases it is advisable to reduce the 
nitrates to ammonia by means of the copper-zinc couple. 
The ammonia is distilled off and determined colorimetric- 
ally. The ammonia originally present in the solution 
must be determined separately and deducted. Nitrites 
are likewise reduced to ammonia and must be allowed for 
if present. 

" Analytical Process. — Evaporate 50 cc, or other 
convenient quantity, depending upon the amount of 
nitrate present, to dryness in a porcelain dish on a water 
bath, removing the dish as soon as it is completely dry. 
Add I cc. of the phenoldisulphonic acid reagent and stir 
thoroughly with the rounded end of a glass rod so as to 



ANALYTICAL PROCESS 91 

loosen the residue and bring the acid well in contact with 
every portion of it. The time of action on the nitrate 
should be about ten minutes. At the end of this time the 
acid is diluted with about 15 cc. of water and made al- 
kaline with ammonium hydroxide, a yellow color being 
developed when the solution becomes alkaline. This is 
then diluted to 50 cc. or 100 cc. and compared with the 
standard colorimetric solution. If the color is too in- 
tense for direct comparison with this standard, an aliquot 
portion may be taken and diluted to definite volume and 
the strength of this determined." 

To clear the soil extracts. Greaves and Hirst (6) found 
the following methods to give good results: The addition 
of 2 grams of lime, ferric sulphate, ferric alum, sodium 
alum, or potassium alum to the soil-water mixture; filter- 
ing through Pasteur-Chamberland filter, or centrifuging. 

To eliminate possible error due to the presence of chlo- 
rides or other inorganic materials, certain reduction 
methods have given better results than the above method. 
The iron reduction method, as described below, was found 
by Greaves and Hirst (6) to give more satisfactory results 
in the presence of inorganic salts and in the presence of 
organic matter than did other methods. The soil is first 
agitated for five minutes with five times its weight of water 
and clarified by one of the methods described above, prefer- 
ably with alum. 

"An aliquot part (100 cc.) of the supernatant liquid is 
pipetted off, and, together with 2 cc. of a saturated solu- 
tion of sodium hydroxide, evaporated to about one-fourth 
of its original volume to free from ammonia. If urea is 
present, it is necessary to evaporate to dryness. To this 
is added 50 cc. of ammonia-free water, 5 grams of 'iron- 
by-hydrogen,' and 30 cc. of sulphuric acid (sp. gr. 1.35). 



92 METHODS OF DETERMINING ALKALI 

If less than 40 mg. of nitric nitrogen is to be determined, 
it is well to take a correspondingly smaller quantity of 
iron and sulphuric acid. The neck of the reduction flask 
is fitted with a 2-hole stopper through which passes a 
50-cc. separatory funnel and a bent tube which dips into 
a vessel containing water to prevent mechanical loss. 
The acid is slowly added and allowed to stand until the 
rapid evolution of hydrogen is over and then heated to 
boiling for ten minutes. The contents of the side vessel 
should be returned to the reduction flask before the re- 
action is complete, thus insuring the complete reduction 
of any nitrates which may have been carried over with 
the first violent evolution of the hydrogen. The contents 
of the reduction flask are transferred to a Kjeldahl flask, 
neutralized with sodium hydroxide, and distilled into 
standard acid. The excess of acid is titrated back with 
standard alkali, lacmoid being used as indicator." 

Nitrates should be determined immediately after sam- 
pling unless some sterilizing material, such as chloroform, 
is added to check bacterial activity. 

Determination of Bases. — Calcium. — The common 
method for determining calcium is to heat a given 
quantity of the solution nearly to boiling, and, after 
adding a few drops of ammonia, to precipitate the 
calcium completely by adding, drop by drop, a hot 
solution of ammonium oxalate. The solution is kept 
at this temperature for about 2 hours after which two 
or three decantations with hot water from the beaker 
containing the solution are passed through a filter. The 
precipitate remaining in the beaker is dissolved with a few 
drops of hydrochloric acid, water is added, and the former 
process of adding ammonia and ammonium oxalate to 
reprecipitate the calcium is repeated. The solution, to- 



DETERMINATION OF BASES 93 

gether with the precipitate, is then poured onto the same 
illter paper as before and thoroughly washed wath hot 
water. Transfer paper to original beaker containing hot 
i:io sulphuric acid. After the paper has been immersed 
in the liquid it is brought up on the side of the beaker by 
means of a glass rod. Then the solution is titrated to the 
end point with potassium permanganate. The paper is 
now put back into the liquid and the titration fmished. 
Some prefer to ignite to constant weight the precipitate 
left on the filter paper and calculate it as calcium oxide. 

Magnesium. — Usually magnesium is determined by the 
method adopted by the Association of Ofiicial Agricultural 
Chemists which is as follows: "Evaporate the filtrate 
from the above determination on water bath to dryness 
and carefully heat to expel ammonium salts. Take up 
the residue, with 20 to 25 cc, hot water and about 5 cc. 
hydrochloric acid, filter, and wash. Concentrate to about 
50 cc, cool, and add sufiicient acid sodium phosphate to 
precipitate the magnesium; then add gradually am- 
monium hydroxide, with constant stirring, until the 
solution is distinctly alkaline. Test with acid-sodium- 
phosphate to be sure that sufficient has been added. Al- 
low to stand one-half hour, then add gradually 10 cc. of 
strong ammonium hydroxide, cover closely to prevent 
escape of ammonia, and let stand in the cold. Filter 
after 12 hours, wash the precipitate free from chlorides, 
using 2.5 per cent ammonia water, dry, burn at first at 
moderate heat, then ignite intensely, and weigh as mag- 
nesium-pyro-phosphate (MgoPoOr)." If this precipita- 
tion is done from a hot solution there is less danger of 
tertiary magnesium phosphate being formed. Colori- 
metric and titration methods are used occasionally. 

Sodium. — Sodium determinations are seldom made in 



94 METHODS OF DETERMINING ALKALI 

alkali studies because the process is long and because the 
quantity present can be roughly estimated by elimination 
when the other easier determinations have been made. 

Other Methods of Determining Soluble Salts. — The 
Electric Bridge. — A modification of the Wheatstone 
bridge has been found of considerable value in de- 
termining the total salts in either soil or water in the 
field without chemical analysis. The theory upon which 
the instrument works is based upon the fact that the re- 
sistance of the solution varies with the concentration of 
its soluble salts. It has been found of great value for de- 
termining the total salts in soils which do not contain ex- 
cessive quantities of organic matter, and especially where 
the salts are mostly sodium chloride and sodium sulphate. 
It becomes unreliable where the organic matter is high 
and it is necessary to determine the sodium carbonate 
separately from the other salts because the resistance is 
considerably different. 

In using the instrument, the soil in the cup is first 
moistened until it becomes saturated or puddled and free 
from air, and if the soil is very dry it should be allowed to 
stand in this condition for about 20 minutes. The cup, 
which is just levelful of the saturated soil, is placed be- 
tween the clips through which the current passes, and 
the pointer is moved back and forth until the neutral point 
is reached where the buzzing in the receiver is at a mini- 
mum. The instrument has coils with 10, 100, and 1000 
ohms resistance, and it is necessary to adjust the coils 
until the proper resistance is found. "The resistance of 
the cup contents is found by multiplying the resistance 
of the comparison coil used, shown on the rotary switch, 
by the number on the scale opposite the pointer, when 
a balance is established. Thus, if the comparison coil 



DETERMINING SOLUBLE SALTS 95 

is lOO and the scale reading 0.92, the resistance of the cup 
is 92 ohms. When the extra 100-ohni coil is used with the 
cup, the 100 ohms adtled must be subtracted from the 
resistance read on the scale. Thus if the 100 ohms is in 
series with the cup and the scale reads 1.2, while the 
comparison coil shows 100 ohms, then the resistance of the 
cup and coil is 120 ohms. Subtracting the 100 ohms of 
the coil leaves 20 ohms as the resistance due to the cup. 
The resistance of the cup contents must be corrected to a 
temperature of 60° F. To do this, immediately after 
reading the resistance, a thermometer is stuck into the cup 
and read after two minutes. The resistance at the tem- 
perature found is then corrected to 60° F. (by means of 
Table XII). Having found the resistance of the cup 
contents, the percentage of salt may be determined for 
soils by use of Table XIII, and for soil solutions by 
Table XIV." In making temperature corrections, which 
must be done before determining the parts per million of 
salts present, the column containing the temperature of 
the soil is found. The sum of the resistances of the sep- 
arate digits corresponding to the resistance at the given 
temperature of the soil is found and the sum of the resist- 
ances of the separate digits corresponding to the resistance 
at the given temperatures is added. "As an example of 
its use, suppose the resistance to be 1349 ohms at 72° F. 
On the left-hand side of the table find 72° F., then opposite 
under the columns marked '1000' will be found 1170 ohms 
at 60° F. as the value of 1000 at 72° F.; 3000 ohms at 72° F. 
will be found equal to 3510 at 60° F.; hence 300 is equal 
to 351 at 60° F., 40 is equal to 46.8 ohms at 60° F,, and 9 is 
equal to 10.5 ohms at 60° F.," and the sum of these re- 
sistances at 60° F. is equal to 1578.3 ohms, w^hich is the 
desired resistance. 



96 



METHODS OF DETERMINING ALKALI 



Table XII. Reduction of the Electrical Resistance of 
Soils to a Uniform Temperature of 6o° F. 



»F. 


100a 


2000 


3000 


4000 


5000 


6000 


7000 


8000 


9000 


32.0 


625 


1,250 


1,875 


2,500 


3,125 


3,750 


4,375 


5,000 


5,625 


32.5 


632 


1,265 


1,897 


2,530 


3,163 


3,795 


4,425 


5,059 


5,691 


33-0 


640 


1,280 


1,920 


2,560 


3,200 


3,840 


4,480 


5,120 


5,760 


33-5 


647 


1,294 


1,941 


2,588 


3,235 


3,883 


4,530 


5,177 


5,824 


34-0 


653 


1,306 


1,959 


2,612 


3,265 


3,918 


4,571 


5,224 


5,877 


34-5 


660 


1,320 


1,980 


2,640 


3,300 


3,960 


4,620 


5,280 


5,940 


35 -o 


668 


1,336 


2,004 


2,672 


3,340 


4,008 


4,676 


5,344 


6,012 


35-5 


675 


1,350 


2,025 


2,700 


3,375 


4,050 


4,725 


5,400 


6,075 


36.0 


683 


1,366 


2,049 


2,732 


3,415 


4,098 


4,781 


5,464 


6,147 


36.S 


690 


1,380 


2,070 


2,760 


3,450 


4,140 


4,830 


5,520 


6,210 


37-0 


698 


1,396 


2,094 


2,792 


3,490 


4,188 


4,886 


5.584 


6,282 


37-5 


704 


1,408 


2,112 


2,816 


3,520 


4,224 


4,928 


5,632 


6,336 


38.0 


711 


1,422 


2,133 


2,844 


3,555 


4,266 


4,977 


5,688 


6,399 


38.5 


717 


1,434 


2,151 


2,868 


3,585 


4,302 


5,019 


5,736 


6,453 


39-0 


723 


1,446 


2,169 


2,892 


3,615 


4,338 


5,061 


5,784 


6,507 


39-5 


729 


1,458 


2,187 


2,916 


3,645 


4,374 


5,103 


5,832 


6,561 


40.0 


735 


1,470 


2,205 


2,940 


3,675 


4,410 


5,145 


5,880 


6,6x5 


40-5 


742 


1,484 


2,226 


2,968 


3,710 


4,452 


5,194 


5,936 


6,678 


41.0 


750 


1,500 


2,250 


3,000 


3,750 


4,500 


5,250 


6,000 


6,750 


41-5 


■757 


1,514 


2,271 


3,028 


3,785 


4,542 


5,299 


6,056 


6,813 


42.0 


763 


1,526 


2,289 


3,052 


3,815 


4,578 


5,341 


6,104 


6,867 


42.5 


770 


1,540 


2,310 


3,080 


3,850 


4,620 


5,390 


6,160 


6,930 


43-0 


776 


1,552 


2,328 


3,104 


3,880 


4,656 


5,432 


6,208 


6,984 


43-5 


782 


1,564 


2,346 


3,128 


3,910 


.4,692 


5,474 


6,256 


7,038 


44.0 


788 


1,576 


2,364 


3,152 


3,940 


4,728 


5,516 


6,304 


7,092 


44-5 


794 


1,588 


2,382 


3,176 


3,970 


4,764 


5,558 


6,352 


7,146 


45-0 


800 


1,600 


2,400 


3,200 


4,000 


4,800 


5,600 


6,400 


7,200 


45-5 


807 


1,614 


2,421 


3,228 


4,035 


4,842 


5,649 


6,456 


7,263 


46.0 


814 


1,628 


2,442 


3,256 


4,070 


4,884 


5,698 


6,512 


7,326 


46.5 


821 


1,642 


2,463 


3,284 


4,105 


4,926 


5,747 


6,568 


7,389 


47.0 


828 


1,656 


2,484 


3,312 


4,14c 


4,968 


5,796 


6,624 


7,452 


47.5 


835 


1,670 


2,505 


3,340 


4,175 


5,010 


5,845 


6,680 


7,515 


48.0 


843 


1,686 


2,529 


3.372 


4,215 


5,058 


5,901 


6,744 


7,587 


48.5 


850 


1,700 


2,550 


3,400 


4,250 


5,100 


5,950 


6,800 


7,650 


49.0 


856 


1,712 


2,568 


3,424 


4,280 


5,136 


5,992 


6,848 


7,704 


49-5 


862 


1,724 


2,586 


3,448 


4,310 


5,172 


6,034 


6,896 


7,758 


50.0 


867 


1,734 


2,601 


3,468 


4,335 


5,202 


6,069 


6,936 


7,803 


50-5 


874 


1,748 


2,622 


3,496 


4,370 


5,244 


6,118 


6,992 


7,866 


Si.o 


881 


1,762 


2,643 


3,524 


4,405 


5,286 


6,167 


7,048 


7,929 


Si-5 


887 


1,774 


2,661 


3,548 


4,435 


5,322 


6,209 


7,096 


7,983 


52.0 


893 


1,786 


2,679 


3,572 


4,465 


5,358 


6,251 


7,144 


8,037 


52-5 


900 


1,800 


2,700 


3,600 


4,500 


5,400 


6,300 


7,200 


8,100 


S3-0 


906 


1,812 


2,718 


3,624 


4,530 


5,436 


6,342 


7,248 


8,154 


53-5 


912 


1,824 


2,736 


3,648 


4,560 


5,472 


6,384 


7,296 


8,208 


54-0 


917 


1,834 


2,751 


3,668 


4,585 


5,502 


. 6,419 


7,336 


8,253 



DETERMINING SOLUBLE SALTS 
Table XII. {Concluded.) 



97 



°1'. 


1000 


2000 


.5000 


4000 


5000 


6000 


6000 


8000 


gooo 


54-5 


925 


1,850 


2,775 


3,700 


4,625 


5,550 


6,475 


7,400 


8,325 


55-0 


933 


1,866 


2,799 


3,732 


4,665 


5,598 


6,531 


7,464 


8,397 


55-5 


940 


1,880 


2,820 


3,760 


4,700 


5,640 


6,580 


7,520 


8,460 


S6.o 


947 


1,894 


2,841 


3,780 


4,735 


5,682 


6,629 


7,576 


8,523 


S6.5 


954 


1,908 


2,862 


3,816 


4,770 


5,724 


6,678 


7,632 


8,586 


S7-0 


961 


1,922 


2,883 


3,844 


4,805 


5,766 


6,727 


7,688 


8,649 


57-S 


968 


1,936 


2,904 


3,872 


4,839 


5,807 


6,775 


7,743 


8,711 


58.0 


974 


1,948 


2,922 


3,896 


4,870 


5,844 


6,818 


7,792 


8,766 


58.5 


981 


1,961 


2,942 


3,923 


4,903 


5,884 


6,864 


7,845 


8,826 


S9-0 


987 


1,974 


2,962 


3,949 


4,936 


5,923 


6,910 


7,898 


8,885 


SQ-5 


994 


1,988 


2,982 


3,976 


4,971 


5,965 


6,959 


7,953 


8,947 


60.0 


1,000 


2,000 


3,000 


4,000 


5,000 


6,000 


7,000 


8,oco 


9,000 


60.5 


1,006 


2,013 


3,019 


4,026 


5,032 


6,039 


7,045 


8,052 


9,059 


6r.o 


1,013 


2,026 


3,039 


4,052 


5,065 


6,078 


7,091 


8,104 


9,117 


61.S 


1,020 


2,040 


3,060 


4,080 


5,100 


6,120 


7,140 


8,160 


9,180 


62.0 


1,027 


2,054 


3,081 


4,108 


5,135 


6,162 


7,189 


8,216 


9,243 


62.S 


1,033 


2,067 


3,100 


4,134 


5,167 


6,201 


7,234 


8,268 


9,302 


63.0 


1,040 


2,080 


3,120 


4,160 


5,200 


6,240 


7,280 


8,320 


9,360 


63.5 


1,047 


2,094 


3,141 


4,188 


5,235 


6,282 


7,329 


8,376 


9,423 


64.0 


1,054 


2,108 


3,162 


4,216 


■5,270 


6,324 


7,378 


8,432 


9,486 


64-5 


1,060 


2,121 


3,181 


4,242 


5,302 


6,363 


7,423 


8,484 


9,545 


65.0 


1,067 


2,134 


3,201 


4,268 


5,335 


6,402 


7,469 


8,536 


9,603 


65-5 


1,074 


2,148 


3,222 


4,296 


5,370 


6,444 


7,518 


8,592 


9,666 


66.0 


1,081 


2,162 


3,243 


4,324 


5,405 


6,486 


7,567 


8,648 


9,729 


66.5 


1,088 


2,176 


3,264 


4,352 


5,440 


6,528 


7,616 


8,704 


9,792 


67.0 


1,095 


2,190 


3,28s 


4,380 


5,475 


6,570 


7,665 


8,760 


9,855 


67.5 


1,102 


2,205 


3,307 


4,410 


5,512 


6,615 


7,717 


8,820 


9,922 


68.0 


1,110 


2,220 


3,330 


4,440 


5,55c 


6,660 


7,770 


8,880 


9,990 


68.5 


1,117 


2,235 


3,352 


4,470 


5,587 


6,705 


7,823 


8,940 


10,058 


69.0 


1,125 


2,250 


3,375 


4,500 


5,625 


6,750 


7,875 


9,000 


10,125 


69-5 


1,133 


2,265 


3,398 


4,530 


5,663 


6,795 


7,928 


9,060 


10,193 


70.0 


1,140 


2,280 


3,420 


4,560 


5,700 


6,840 


7,980 


9,120 


10,260 


70-5 


1,147 


2,285 


3,442 


4,590 


5,737 


6,88s 


8,032 


9,180 


10,327 


71.0 


i,iSS 


2,310 


3,465 


4,620 


5,775 


6,930 


8,085 


9,240 


10,395 


71-5 


1,162 


2,325 


3,487 


4,650 


5,812 


6,975 


8,137 


9,300 


10,462 


72.0 


1,170 


2,340 


3,510 


4,680 


5,850 


7,020 


8,190 


9,360 


10,530 


72.S 


1,177 


2,355 


3,532 


4,710 


5,887 


7,065 


8,242 


9,420 


10,597 


73-0 


i,i8s , 


2,370 


3,555 


4,740 


5,925 


7,110 


8,295 


9,480 


10,665 


73-5 


1,193 


2,386 


3,579 


4,772 


5,965 


7,158 


8,351 


9,544 


10,737 


74.0 


1,201 


2,402 


3,603 


4,804 


6,005 


7,206 


8,407 


9,608 


10,809 


74-5 


1,208 


2,416 


3,624 


4,832 


6,040 


7,248 


8,456 


9,664 


10,872 


75 -o 


1,215 1 


2,430 


3,645 


4,860 


6,075 


7,290 


8,505 


9,720 


10,935 


7S-S 


1,222 1 


2,445 


3,667 


4,890 


6,112 


7,335 


8,557 


9.780 


11,002 


76.0 


1,230 1 


2,460 


3,690 


4,920 


6,150 


7,380 


8,610 


9,840 


11,070 


76.S 


1,237 ' 


2,475 


3,712 


4,950 


6,187 


7,425 


8,662 


9,900 


11,137 



98 METHODS OF DETERMINING ALKALI 

Table XIL {Conlinued.) 



"F. 


1000 


2000 


3000 


4000 


5000 


6000 


7000 


8000 


9000 


77.0 


1,24s 


2,490 


3,735 


4,980 


6,225 


7,470 


8,71s 


9,960 


11,205 


77-5 


1,253 


2,506 


3,759 


5,012 


6,265 


7,518 


8,771 


10 


024 


11,277 


78.0 


1,261 


2,522 


3,783 


5,044 


6,305 


7,566 


8,827 


10 


088 


11,349 


78.S 


1,269 


2,538 


3,807 


5,076 


6,345 


7,614 


8,883 


10 


152 


11,421 


79.0 


1,277 


2,554 


3,831 


5,108 


6,385 


7,662 


8,939 


10 


216 


11,493 


79-5 


1,285 


2,576 


3,856 


5,142 


6,427 


7,713 


8,998 


10 


284 


11,569 


80.0 


1,294 


2,598 


3,882 


5,176 


6,470 


7,764 


9,058 


10 


352 


1 1 ,646 


80.S 


1,302 


2,609 


3,906 


5,208 


6,510 


7,812 


9,114 


10 


416 


11,718 


81.0 


1,310 


2,620 


3,930 


5,240 


6,550 


7,860 


9,170 


10 


480 


11,790 


81.S 


1,318 


2,637 


3,955 


5,274 


6,592 


7,911 


9,229 


10 


546 


11,866 


82.0 


1,327 


2,654 


3,981 


S.308 


6,63s 


7,962 


9,289 


10 


616 


11,943 


82.S 


1,335 


2,670 


4,005 


5,340- 


6,67s 


8,010 


9,345 


10 


680 


12,015 


83.0 


1,343 


2,686 


4,029 


5,372 


6,715 


8,058 


9,401 


10 


744 


12,087 


83-5 


1,351 


2,702 


4,053 


5,404 


6,755 


8,106 


9,457 


10 


808 


12,159 


84.0 


1,359 


2,718 


4,077 


5,436 


6,795 


8,154 


9,513 


10 


872 


12,231 


84.5 


1,367 


2,735 


4,102 


5,470 


6,837 


8,205 


9,572 


10 


940 


12,3^7 


85.0 


1,376 


2,752 


4,128 


5,504 


6,830 


8,256 


9,632 


II 


008 


12,384 


85-S 


1,385 


2,769 


4,153 


5,538 


6,922 


8,307 


9,691 


II 


076 


12,460 


86.0 


1,393 


2,786 


4,179 


5,572 


6,965 


8,358 


9,751 


II 


144 


12,537 


86.S 


1,401 


2,802 


4,203 


5,604 


7,005 


8,406 


9,807 


II 


208 


12,609 


87.0 


1,409 


2,818 


4,227 


5,636 


7,04s 


8,454 


9,863 


II 


272 


12,681 


87-5 


1,418 


2,836 


4,254 


5,672 


7,090 


8,508 


9,931 


II 


344 


12,762 


88.0 


1,427 


2,854 


4,281 


5,708 


7,135 


8,562 


9,989 


II 


416 


12,843 


88.5 


1,435 


2,870 


4,305 


5,740 


7,175 


8,610 


10,040 


II 


480 


12,915 


89.0 


1,443 


2,886 


4,329 


5,772 


7,215 


8,658 


10,091 


II 


544 


12,987 


89.5 


1,451 


2,903 


4,354 


5,806 


7,257 


8,709 


10,155 


II 


612 


13,063 


90.0 


1,460 


2,920 


4,380 


5,840 


7,300 


8,760 


10, 22c 


II 


680 


13,140 


90-S 


1,468 


2,937 


4,405 


5,874 


7,342 


8,811 


10,279 


II 


748 


13,216 


gi.o 


1,477 


2,954 


4,431 


5,908 


7,385 


8,862 


10,339 


II 


816 


13,293 


9I-S 


1,486 


2,972 


4,458 


5,944 


7,430 


8,916 


10,402 


II 


888 


13,374 


92.0 


1,495 


2,990 


4,485 


5,980 


7,475 


8,970 


10,465 


II 


960 


13,45s 


92.5 


1,504 


3,008 


4,512 


6,016 


7,520 


9,024 


10,528 


12 


032 


13,536 


93-0 


1,513 


3,026 


4,539 


6,052 


7,565 


9,078 


10,591 


12 


104 


13,617 


93-S 


1,522 


3,035 


4,567 


6,090 


7,612 


9,135 


10,657 


12 


180 


13,7 2 


94.0 


1,532 


3,064 


4,596 


6,128 


7,660 


9,192 


10,724 


12 


256 


13,788 


94-5 


1,541 


3,083 


4,624 


6,166 


7,707 


9,249 


10,790 


12 


332 


13,873 


95 -o 


1,551 


3,102 


4,653 


6,204 


7,755 


9,306 


10,857 


12 


408 


13,959 


9S-S 


1,560 


3,121 


4,681 


6,242 


7,802 


9,363 


10,923 


12 


484 


14,040 


96.0 


1,570 


3,140 


4,710 


6,280 


7,850 


9,420 


10,990 


12 


560 


14,130 


96.S 


1,580 


3,160 


4,740 


6,320 


7,900 


9,480 


11,060 


12 


640 


14,220 


97.0 


1,590 


3,180 


4,770 


6,360 


7,950 


9,540 


11,130 


12 


720 


14,310 


97.5 


1,600 


3,201 


4,801 


6,402 


S,002 


9,603 


11,203 


12 


804 


14,404 


98.0 


1,611 


3,222 


4,833 


6,444 


8,05s 


9,666 


11,277 


12 


888 


14,499 


98.S 


1,620 


3,240 


4,860 


6,480 


8,100 


9,720 


11,340 


12 


960 


14,580 


99.0 


1,629 


3,258 


4,887 


6,516 


8,14s 


9-774 


11,403 


13 


032 


14,661 



DETERMINING SOLUBLE SALTS 



99 



Tablk XIII. Soluble Salts in Soil Solutions of Various Resistances 
AT 60° F. 



Rat 


Parts 


R. at 


Parts 


R. at 


Parts 


R. at 


Parts 


R. at 


Parts 


R at 


Parts 


R. at 


1 
Parts 


63" 


per 


60° 


per 


do" 


Iier 


()o" 


jicr 


do" 


per 


do" 


per 


do" 


per 


J.- 


mil- 


1.-. 


mil- 


I.- 


mil- 


[.■ 


mil- 


[. 


mil- 


!••. 


mil- 


1.* 


mil- 




lion 




lion 




lion 




lion 




lion 


lion 


I . 


lion 


68 


3500 


118 


869 


168 


268 


218 


945 


268 


731 


318 


620 


366 


549 


60 


400 


119 


8si 


169 


260 


219 


940 


269 


728 


319- 


618 


366.5 


548 


70 


300 


120 


834 


170 


252 


220 


935 


270 


72s 


320 


616 


367 


547 


71 


250 


121 


817 


171 


244 


221 


930 


271 


722 


321 


614 


367 -5 


546 


7- 


200 


122 


800 


172 


236 


222 


92s 


272 


719 


322 


612 


368 


545 


7.? 


150 


123 


783 


173 


228 


223 


920 


273 


716 


323 


610 


368. 5 


544 


74 


1 00 


124 


766 


174 


220 


224 


91S 


274 


713 


324 


608 


369 


543 


75 


SO 


125 


749 


175 


212 


225 


910 


275 


710 


325 


606 


369.5 


542 


7" 


,5000 


126 


732 


176 


205 


226 


905 


276 


707 


326 


604 


370 


541 


77 


2950 


127 


715 


177 


198 


227 


900 


1 277 


704 


327 


602 


370.5 


540 


78 


900 


128 


1700 


178 


191 


228 


89s 


278 


701 


328 


600 


371 


539 


7Q 


850 


129 


68s 


179 


184 


229 


890 


279 


698 


329 


598 


3715 


538 


80 


800 


130 


670 


180 


177 


230 


S8s 


280 


696 


330 


596 


372 


537 


81 


767 


131 


65 s 


181 


170 


231 


880 


281 


694 


33 1 


S91 


372-5 


,536 


82 


733 


132 


640 


182 


163 


232 


87s 


282 


692 


332 


592 


373 


535 


8,? 


700 


133 


626 


183 


156 


233 


870 


283 


690 


333 


S90 


373.5 


534 


84 


667 


134 


613 


184 


140 


234 


86s 


284 


688 


334 


S88 


374 


533 


8s 


633 


135 


600 


185 


142 


23s 


860 


28s 


686 


^.^r, 


S86 


3745 


532 


86 


600 


136 


S87 


1 86 


135 


236 


8S5 


286 


684 


336 


584 


375 


531 


87 


571 


137 


574 


1S7 


128 


237 


850 


287 


682 


337 


582 


37SS 


S30 


88 


542 


138 


562 


188 


1121 


238 


845 


288 


68o 


338 


S°o 


376 


529 


89 


5 13 


139 


SSo 


189 


1114 


239 


840 


289 


678 


339 


578 


376.5 


528 


90 


484 


140 


538 


190 


107 


240 


83s 


290 


676 


340 


577 


377 


527 


91 


456 


141 


527 


igi 


100 


241 


830 


291 


674 


341 


576 


377. S 


526 


92 


427 


142 


S16 


192 


93 


242 


82s 


292 


672 


342 


575 


378 


52s 


93 


400 


143 


505 


193 


86 


243 


820 


293 


670 


343 


574 


378. s 


524 


94 


375 


144 


494 


194 


80 


244 


815 


294 


668 


344 


573 


379 


523 


95 


3SO 


145 


483 


195 


74 


24s 


810 


295 


666 


345 


572 


3795 


522 


96 


325 


146 


472 


196 


68 


246 


805 


296 


664 


346 


571 


380 


521 


97 


300 


147 


461 


197 


62 


247 


800 


297 


662 


347 


5 70 


380. s 


520 


98 


276 


148 


4SO 


198 


S6 


248 


796 


298 


660 


348 


569 


381 


519 


99 


253 


149 


440 


199 


50 


249 


792 


299 


658 


349 


568 


381 . 5 


518 


100 


230 


150 


430 


300 


44 


250 


788 


300 


6s6 


350 


567 


382 


SI7 


101 


208 


151 


420 


201 


38 


251 


784 


301 


654 


351 


566 


382.5 


516 


102 


186 


IS2 


410 


202 


32 


252 


780 


302 


652 


352 


565 


383 


5IS 


103 


164 


I S3 


400 


203 


26 


253 


776 


303 


650 


3S5 


564 


383. 5 


514 


104 


142 


IS4 


390 


204 


20 


254 


773 


304 


648 


354 


563 


384 


513 


los 


121 


155 


380 


205 


14 


255 


770 


305 


646 


355 


56» 


384.5 


512 


106 


100 


156 


370 


206 


8 


256 


767 


306 


644 


356 


561 


385 


511 


107 


79 


IS7 


360 


207 


2 


257 


764 


307 


642 


357 


560 


386 


510 


loS 


59 


IS8 


350 


208 


996 


258 


761 


308 


640 


358 


559 


386.5 


S09 


log 


30 


159 


341 


209 


990 


259 


758 


309 


638 


359 


558 


387 


S08 


110 


90 


160 


332 


210 


98s 


260 


755 


310 


636 


360 


557 


387. 5 


507 


III 


2000 


161 


324 


211 


980 


261 


752 


311 


634 


361 


556 


388 


506 


112 


1981 


162 


316 


212 


975 


262 


749 


312 


632 


362 


555 


389 


SOS 


113 


962 


163 


308 


213 


970 


263 


746 


313 


630 


363 


554 


390 


504 


114 


943 


164 


300 


214 


965 


264 


743 


314 


628 


364 


553 


390. 5 


503 


115 


924 


165 


292 


215 


960 


265 


740 


31S 


626 


364 -5 


552 


391 


S02 


116 


90s 


166 


284 


216 


955 


266 


737 


316 


624 


36s 


551 


391 5 


501 


117 


887 


167 


276 


217 


9SO 


267 


734 


317 


622 


365. S 


550 


392 


500 



100 METHODS OF DETERMINING ALKALI 



Table XIII. {Continued.) 



R. at 


Parts 


R. at 


Parts 


R. at 


Parts 


R. at 


Parts 


R. at 


Parts 


R. at 


Parts 


R. at 


60° 
F. 


per 
mil- 
lion 


60° 
F. 


per 
mil- 
lion 


60° 
F. 


per 
mil- 
lion 


60° 
F. 


per 
mil- 
lion 


60° 
F. 


per 
mil- 
lion 


60° 
F. 


per 
mil- 
lion 


60° 
F. 


3925 


499 


433.8 


449 


483.2 


399 


549.5 


349 


636 


299 


754 


249 


924 


393 


498 


434.6 


-448 


484.4 


398 


551 


348 


638 


298 


757 


248 


928 


393-5 


497 


435-4 


447 


485.6 


397 


552-5 


347 


640 


297 


760 


247 


932 


394 


496 


436.2 


446 


486.8 


396 


554 


346 


642 


296 


762 


246 


936 


394-5 


495 


437 


4 5 


488 


395 


555-5 


345 


644 


295 


76s 


245 


940 


395 


494 


438-0 


444 


489.2 


394 


557 


344 


646 


294 


768 


244 


944 


396 


493 


439-0 


443 


490.4 


393 


558.5 


343 


648 


293 


771 


243 


948 


397 


492 


440.0 


442 


491.6 


392 


560 


342 


650 


292 


774 


242 


953 


398 


491 


441.0 


441 


492.8 


391 


561.5 


341 


652 


291 


777 


241 


958 


399 


490 


442 


440 


494 


390 


563 


340 


654 


290 


780 


240 


962 


400 


489 


442-8 


439 


495 


389 


56s 


339 


656 


289 


783 


239 


966 


400.8 


488 


443-6 


438 


496 


388 


567 


338 


658 


288 


786 


238 


971 


401 .6 


487 


444-4 


437 


497-5 


387 


568.5 


337 


661.5 


287 


789 


237 


976 


402.4 


486 


445-2 


436 


499 


386 


570 


336 


663 


286 


702 


236 


981 


403 


485 


446 


435 


Soo 5 


385 


571.5 


335 


66s 


28s 


795 


235 


98s 


403.8 


484 


447 


434 


502 


384 


573 


334 


667 


284 


798 


234 


990 


404.6 


483 


448 


433 


503 


383 


574.5 


333 


669. 5 


2S3 


801 


233 


995 


405-4 


482 


449 


432 


504 


382 


576 


332 


672 


282 


804 


232 


1000 


406. 2 


481 


450 


431 


S05-5 


381 


578 


331 


674 


281 


807 


231 


1005 


407 


480 


451 


430 


507 


380 


s8o 


330 


676 


280 


811 


230 


lOIO 


407.8 


479 


452 


429 


508 


379 


581. 5 


329 


678. 5 


279 


814 


229 


1016 


408.6 


478 


453 


428 


S09 


378 


583 


328 


681 


278 


817 


228 


1022 


409.4 


477 


454 


427 


510. S 


377 


584.5 


327 


683 


277 


820 


227 


1027 


410. 2 


476 


455 


426 


512 


376 


586 


326 


685 


276 


824 


226 


1032 


411 


475 


4S6 


425 


513 


375 


587.5 


325 


687.5 


275 


827 


225 


1038 


411. 8 


474 


457 


424 


S14 


374 


589 


324 


690 


274 


830 


224 


1044 


412.6 


473 


458 


423 


SiS-5 


373 


591 


323 


692.5 


273 


834 


223 


1049 


413-4 


472 


459 


422 


517 


372 


593 


322 


695 


272 


837 


222 


loss 


414.2 


471 


460 


421 


518. S 


371 


594-5 


321 


697.5 


271 


841 


221 


1060 


415 


470 


461 


420 


520 


370 


596 


320 


700 


270 


844 


220 


1067 


415.8 


469 


462 


419 


521 


369 


598 


319 


702 


269 


848 


219 


1073 


416.6 


468 


463 


418 


522 


368 


600 


318 


704 


268 


851 


218 


1079 


417-4 


497 


464 


417 


523.5 


367 


601. s 


317 


707 


276 


854 


217 


1085 


418.2 


466 


465 


416 


525 


366 


603 


3X6 


709 


266 


858 


216 


logi 


419 


465 


466 


415 


526 


36s 


60s 


315 


712 


265 


862 


215 


1097 


420 


464 


467 


414 


527 


364 


607 


314 


71S 


264 


865 


214 


1 104 


421.0 


463 


468 


413 


528.5 


363 


609 


313 


717 


263 


869 


213 


mo 


422.0 


462 


469 


412 


530 


362 


611 


312 


720 


262 


872 


212 


1118 


423.0 


461 


470 


411 


531 -5 


361 


612. s 


311 


722 


261 


876 


211 


II2S 


424 


460 


471 


410 


533 


360 


614 


310 


725 


260 


S80 


210 


1132 


424.8 


459 


472.2 


409 


534- S 


359 


616 


309 


727 


259 


884 


209 


1 140 


42s -6 


458 


473.4 


408 


536 


358 


618 


308 


730 


258 


887 


208 


1147 


426.4 


457 


474.6 


407 


537.5 


357 


620 


307 


732 


257 


891 


207 


"54 


427.2 


456 


475-8 


406 


539 


356 


622 


306 


735 


256 


895 


206 


1161 


428.0 


455 


477 


405 


540-5 


355 


624 


305 


738 


255 


899 


20s 


1 168 


429.0 


454 


478 


404 


542 


354 


626 


304 


740 


254 


903 


204 


1176 


430.0 


453 


479 


403 


543-5 


353 


628 


303 


743 


253 


907 


203 


1 184 


431 -o 


452 


480 


402 


545 


352 


630 


302 


746 


252 


911 


202 


1192 


432.0 


451 


^81 


401 


546.5 


351 


632 


301 


749 


251 


915 


201 


1200 


433 


450 


482 


400 


548 


3SO 


634 


300 


751 


250 


920 


200 


1208 



DETERMINING SOLUBLE SALTS 

Table XIII. (Continued.) 



101 



R.at 

60° 
F. 


Parts 




Parts 




Parts 




Parts 


R. at 

60° 
F. 


Parts 




Parts 




Parts 


per 


K. at 


per 


k. at 


per 


R. at 


per 


per 


R. at 


per 


R.at 


per 


mil- 


60" 


mil- 


60" 


mil- 


60° 


mil- 


mil- 


60° 


mil- 


60° 


mil- 


lion 


F. 


lion 
120 


J-'. 


lion 


F. 


lion 


lion 


F. 


lion 


F. 


lion 


1216 


149 


1394 


1629 


109 


1972 


89 


2S22 


69 


34SO 


49 


5340 


29 


1224 


148 


1404 


128 


1645 


108 


1991 


88 


2555 


68 


3508 


48 


S500 


28 


1232 


147 


1414 


127 


1661 


107 


201 1 


87 


2593 


67 


3576 


47 


5660 


27 


1240 


146 


1423 


126 


1678 


106 


2033 


86 


2631 


66 


3648 


46 


5820 


26 


1248 


145 


1433 


125 


1695 


los 


2055 


8S 


2670 


65 


3717 


45 


6020 


25 


I2S7 


144 


1443 


124 


1712 


104 


2079 


84 


2712 


64 


3788 


44 


6260 


24 


1265 


143 


1453 


123 


1729 


103 


210? 


83 


2755 


63 


3858 


43 


6560 


23 


1274 


142 


I4t)4 


122 


1746 


102 


2128 


82 


2798 


62 


3935 


42 


6980 


22 


1283 


141 


1475 


121 


1763 


lOI 


2152 


81 


2842 


61 


4005 


41 


7240 


21 


1292 


140 


i486 


120 


1780 


100 


2177 


80 


2886 


60 


4090 


40 


7600 


20 


1301 


130 


1408 


119 


1797 


99 


2203 


79 


2932 


59 


4180 


39 


7900 


19 


1310 


138 


ISOQ 


118 


1814 


98 


2232 


78 


2978 


58 


4275 


38 


82SO 


18 


1320 


137 


1520 


"7 


1 83 1 


97 


2259 


77 


302s 


57 


4375 


37 


8800 


17 


1328 


130 


1533 


116 


1848 


9b 


2288 


76 


3071 


56 


4475 


36 


9300 


16 


1337 


13s 


1546 


115 


1865 


95 


2320 


75 


3120 


55 


4S8o 


35 


9700 


155 


1346 


134 


1559 


114 


1882 


94 


2351 


74 


3170 


54 


469s 


34 


10087 


IS 


I3SS 


133 


1572 


113 


1900 


93 


2383 


73 


3220 


S3 


4810 


ii 


10200 


149 


1365 


132 


1585 


112 


1918 


92 


2416 


72 


3277 


52 


492s 


32 






1374 


131 


1599 


III 


1936 


91 


2451 


71 


3336 


51 


5050 


31 






I3«4 


130 


1614 


no 


1954 


90 


2486 


70 


3394 


50 


5195 


30 







Table XIV. Percentage of Mixed Salts in Soil Types with 
A Given Resistance 



Resist- 
ance at 
60° F. 


Sand 


Loam 


loam 


ay 


Resist- 
ance at S 
60° F. 


and L 


cam 1 


:iay , 

oam 


:iay 


Ohms 


Per cent 


Per cent 


Percent Pet 


cent 


Ohms Pe 


r cent Pc 


r cent Pe 


r cent Pe 


r cent 


18 


3.00 


3.00 






95 


35 


37 


39 


42 


19 


2.40 


2.b4 


3 


00 




100 


Zl 


35 


37 


39 


20 


2.20 


2.42 


2 


80 3 


00 


105 


31 


li 


35 


il 


25 


150 


1.70 


I 


94 2 


20 


IIO 


30 


32 


IZ 


35 


30 


1.24 


I 34 


I 


46 I 


5S 


"5 


28 


29 


31 


2,?, 


35 


I .04 


1. 14 


I 


22 I 


32 


120 


27 


28 


29 


?,^' 


40 


.86 


•94 


I 


04 I 


14 


125 


^S 


26 


28 


30 


45 


•75 


.78 




88 


98 


130 


24 


25 


26 


28 


50 


.67 


•71 




77 


86 


135 


23 


24 


25 


27 


55 


.60 


.64 




69 


77 


140 


22 


23 


24 


26 


60 


•55 


•5« 




63 


70 


145 


21 


22 


23 


25 


65 


•51 


•54 




57 


63 


150 


21 


21 


22 


24 


70 


.48 


•50 




53 


59 


155 


20 


21 


21 


23 


75 


•45 


•47 




50 


55 


160 


20 


20 


21 


22 


80 


.42 


•44 




47 


51 


165 


19 


20 


20 


21 


85 


•39 


•42 




44 


48 


170 


19 


19 


20 


20 


90 


■2,1 


•39 




41 


45 













102 



METHODS OF DETERMINING ALKALI 



In using the bridge, Beam and Freak (2) found it pos- 
sible to eliminate calcium sulphate from the total salts 
by using 40 per cent alcohol in extracting the salt and 
comparmg the resistance with that found for this solvent 
under known conditions. By determining both alcohol 
and water extraction results, the difference shows the 
calcium sulphate. 




Fig. 14. — Determining Soluble Salts with the Electric 
Bridge in the Field. 



Freezing-point Method. — A method for determining 
the total soluble salts in soils by means of differences in 
the lowering of the freezing point due to differences in 
concentration of the soil solution, has been worked out by 
Bouyoucos and McCool (3). About an inch of the soil is 
placed in an isolated tube surrounded by salt-ice water 
with a temperature of abgut — 4.5° C. and a delicate 
Beckmen thermometer inserted in the soil. The soil is 
first supercooled to about i degree C. below its freezing 
point and is then disturbed so that the temperature rises 



REFERENCES 103 

until it remains constant for some time. This maximum 
temperature is recorded as the freezing point of the soil. 
By this method, as by the electric bridge, the quantity 
of moisture in the soil plays an important part in the 
concentration of the solution, hence it is essential that 
a constant cjuantity of water be present. Fine soils 
show the iniluence of changes in moisture content much 
more than do sands or other coarse soils. In this method, 
as with the bridge, the determination is indirect and to 
get the total salts the depression of the freezing point must 
be referred to the depression of soils under similar con- 
ditions with knowii c}uantities of salts. The limitations 
of the method haAe not been worked out as yet, but much 
is hoj)ed from it. 

Biological Method. — xA.nother indirect method being 
developed by biologists is based on the effect of alkali salts 
on bacterial action. This method has been extensively 
used by Lipman, Greaves, and Brown and their co-workers 
and depends on the iniluence of soluble salts on the am- 
monifying, nitrifying, and nitrogen-hxing organisms. Sev- 
eral experimenters have noted that the change in the 
quantity of salts present in soils affects the soil flora 
semewhat in proportion, but to what extent this activity 
may be taken as an indication of the salts present is yet 
to be seen. 

REFERENCES 

1. Barnes, J. H., and Au, Barkat. Alkali Soils: Some Biochemical 

Factors in Their Reclamation. Agr. Jour. India, 12 (1917), pp. 368- 
389. (Abs. E. S. R. 38, p. 815.) 

2. Beam, W., and Freak, G. A. An Improvement in the Electrical 

Method of Detorminins; Salt in Soil. Cairo Sci. Jour. 8 (1914), 
pp. 130-133. (Abs. E. S. R. 32, p. 806.) 

3. BouYOUCOs, G. J., and McCool, M. M. The Freezing-point Method 

as a Means of ISIeasuring the Concentration of the Soil Solution 



104 METHODS OF DETERMINING ALKALI 

Directly in the Soil. Mich. Sta. Tech. Bui. 24 (1915), 44 pp.; also 
Jour. Agr. Res. 15 (1918), pp. 331-336. 

4. Cameron, F. K. Estimation of Alkali Carbonates in the Presence of 

Bicarbonates. Am. Chem. Jour. 23 (1900), pp. 471-486. 

5. Davis, R. O. E., and Bryan, H. The Electrical Bridge for the De- 

termination of Soluble Salts in Soils. U. S. D. A. Bur. Soils Bui. 61 
(1910), 36 pp. 

6. Greaves, J. E., and Hirst, C. T. Some Factors Influencing the Quan- 

titative Determination of Nitric Nitrogen in the Soil. Soil Sci. 4 
(1917), pp. 179-203- 

7. Hare, R. F. A Review and Discussion of Some of the Methods for 

the Determination of Alkali Soils. N. Mex. Sta. Biil. 95 (1915), 
pp. 7-16. 

8. PiTTMAN, D. W. A Study of Methods of Determining Soil Alkali. 

Utah Sta. Bui. 170 (1919), 21 pp. 

9. ScHREiNER, O., and Failyer, G. H. Colorimetric, Turbidity, and 

Titration Methods Used in Soil Investigations. U. S. D. A. Bur. 
Soils, Bui. 31 (1906), 160 pp. 

10. Skinner, W. W. A Method for the Determination of Black Alkali 

in Irrigating Waters and Soil E.xtracts. Jour. Am. Chem. Soc. 
28 (1906), pp. 77-80. 

11. Stewart, R., and Greaves, J. E. The Influence of Chlorine on the 

Determination of Nitrates by the Phenoldisulphonic Acid Method. 
Jour. Am. Chem. Soc. 35 (1913), pp. 579-582. 

12. Vinson, A. E., and Catlin, C. N. Study of Methods Used in Alkali 

Determinations. Ariz. Sta. 24 Ann. Rpt. (1913), pp. 274-277. 

13. Wiley, H. W. Official and Provisional Methods of Analysis. U. S. 

D. A. Bur. Chem. Bui. 107 (Revised) (1908), pp. 272. 



CHAPTER VIII 
CHEMICAL EQUILIBRIUM AND ANTAGONISM 

The soil is not static but is in a state of constant change. 
The numerous chemical compounds of which it is com- 
posed are made to react with one another by the con- 
tinuous variation in such factors as temperature, moisture, 
decomposition of organic matter, the growth of plant 
roots, and the activities of microorganisms. These 
agencies of change make it practically impossible to main- 
tain in the soil for any length of time a stable equilibrium. 
This renders an understanding of the alkali problem very 
difJEicult, since the concentration of salts in any particular 



Table XV. Parts of Salts Soluble in ioo Parts of Water ' 
(Compiled from Handbook of Physics and Chemistry, 19 19) 



Tem- 
per- 
ature 


N-TiCOs 


Na2S04 


CaCh 


INIgCb 


MgSOi 


CaS04 


NaCl 


NaNOj 


0° 
20 
30 


7 
21 
40 
46_ 

5}_ 
47 
45 
45 


I 
4 
9 




5 
6 
2 





M 


5 
19 
40 

46 
43 
42 




4 


_9 

8 
7 
7 


q 



59 
74 

lOI 


5 
5 






52 
54 

66 
73 


8 

5 





q 


26 

35 
40 

50 
64 
73 



6 
9 

4 
2 
8 




K 

q 


.179 

.206 


35-6 
35-8 
36.1 


730 
88.0 


31-8 








04 














324 

















35-1 


< 








.178 


36 -7 
38.0 

39- 1 




5° 

80 

100 




w 


132 
147 
159 







114. 
148.0 

175-5 



^ The figures are given in terms of the anhydrous salt, but the solubili- 
ties quoted are for those hydrates which are stable at the stated temperature. 



106 CHEMICAL EQUILIBRIUM AND ANTAGONISM 

zone of the soil is not always the same. Salts readily 
move through the soil and, on coming in contact with other 
salts, chemical changes result. The toxicit}- of the salts 
is also altered by the presence of other salts. 

Solubility of Alkali Salts. — The solubility of the salts 
commonly concerned with alkali work is presented in 
Table XV. ' ' 

The wide difference in the solubility of the salts and the 
importance of temperature is brought out from the above 
figures. It will be noticed, however, that the quantity 
of salts which may dissolve in water is several times the 
quantity ordinarily found in extracts of soil from alkali 
lands. 

Mass Action. — ■ In the discussion of alkali it is generally 
assumed that the salts are stable or retain the same com- 
position as they do in a simple solution. This stable con- 
dition is not found, however. Analyses of different depths 
of alkali soil, for instance, have indicated an apparent 
change, under certain conditions, of part of the harmful 
sodium carbonate into the much less toxic sodium bicar- 
bonate as it was brought close to the surface where there 
was more carbonic acid. 

In order that a clearer understanding of the conditions 
favoring changes in the nature of the salts in the soil 
may be had, a short discussion of the "Law of the Mass 
Action" seems desirable. . This law states that the amount 
of chemical action is proportional to the active mass, or 
molecular concentration of each of the reacting substances, 
in unit volume. Quantitatively, this law may be expressed 
in its most general form as follows: 

Assume the reaction 

nA -\- mB + • - - ti; pX + qY + - • • 



MASS ACTION 107 

to take place so that ;/ moles of A arc capable of reacting 
with m moles of B to form p moles of A' and q moles of Y, 
or vice versa if the number of moles of yl, ^, . . . X, Y, 
. . . actually present in unit volume of the reacting mixture 
are represented respectively by Ci, Q, . . . di, d^, . . ., 
and further if sufficient time be allowed to permit the 
system to come to equilibrium, then at a given temperature 
the condition of the system is expressed by the equation 

di^d." 

= a constant. 

Ci C-i 

This relation is readily understood when one considers 
that a chemical reaction takes place as a result of very 
minute particles (molecular or ionic) of the reacting ma- 
terials coming into intimate contact with each other. 
Obviously the amount of chemical action will depend on 
the number of these particles present in a given volume. 
Moreover, if one of these materials is in great excess in 
the system, it would be expected that the substance with 
which it tended to react would at equilibrium be nearly 
all used up. 

In the case of solutions of inorganic salts, the reactions 
are for the most part ionic and take place therefore with 
great rapidity. It also frequently happens that one of 
the reacting bodies is only slightly soluble, and this fact 
predisposes the reaction in favor of its continued forma- 
tion. But as no salt can be said to be completely insolu^ 
ble, it is quite possible for a reaction to take place, having 
a so-called insoluble substance as one of the starting 
materials. 

For example, consider the reaction 

NaaCOs + CaClo ^ 2 NaCl + CaCOa 
which normally proceeds from left to right on account of 



108 CHEMICAL EQUILIBRIUM AND ANTAGONISM 

the insolubility of calcium carbonate. The mass law 
states that at a given temperature 

(NaCl)2(CaC0.3) 



(Na2C03)(CaClo) 



= a constant, 



where each one of the factors of the equation represents 
the concentration in moles of that constituent in unit 
volume. Though the factor (CaCOs) is very small it is 
not zero and accordingly if water containing a large amount 
of sodium chloride were passed over limestone there would 
be a tendency for calcium carbonate to be changed into 
sodium carbonate and calcium chloride, in order that this 
equation might be fulfilled. 

This latter condition has been found to exist in certain 
parts of Egypt where the soil contained excessive quantities 
of sodium chloride and also contained calcium carbonate. 
Instead of the reaction being Na2C03 + CaCl = 2 NaCl 
+ CaCOs, as is generally the case where these substances 
are brought in contact with each other in somewhat equal 
molecular concentrations, the reverse reaction took place, 
forming black alkali and calcium chloride. As seen in 
the above table of solubilities, calcium chloride is very 
soluble and might easily be washed from the soil so that 
the above reaction might under certain conditions result 
in the formation of considerable black alkali. In like 
manner, other apparently stable salts might, by changes 
in molecular concentrations, react to form new substances 
not possible under ordinary conditions, and in case one or 
both of the end products were taken from the active mass, 
there might be a profound change in the composition of 
the chemical compounds. 

CaHfornia experiments (4) show that up to a strength 
of about 4000 parts per million of sodium sulphate, this 



ABSORPTION OF SALTS BY SOILS 109 

substance could be made to change into sodium carl}()nate 
in the presence of precipitated calcium carbonate through 
which carbon dioxide was being forced, but that the action 
was most vigorous when the strength of sodium sulphate 
was only 750 parts per million. This is the probable ex- 
planation of the fact discovered by certain investigators (5) 
that black alkah was formed about the roots of plants 
growing on white alkali. The carbon dioxide given off 
by the roots of the plants made the calcium carbonate 
soluble so that it would react with the white alkali to form 
the black. 

Salts concentrated in some part of the soil by former 
reactions might be acted upon by solutions borne from dif- 
ferent sections containing other types of salts making 
possible incessant and complete exchanges of ions of the 
different salts. Referring again to the table of solubil- 
ities, it is seen that salts do not maintain the same relative 
solubility at all temperatures. This disturbs the equi- 
librium as the temperature of the soil changes. 

Absorption of Salts by Soils. — The alkali problem would 
be much simplified if the soluble salts were simply held 
in the active part of the soil solution. With such a con- 
dition it would take but a few leachings of the soil to free 
it of excessive salts. Through absorption and adsorption, 
however, the soil tends to hold part of the salts when it is 
drained. With high concentrations the soil has little 
power to hinder free movement of salts, but with lower 
concentrations the soil retains a larger proportion of the 
salts. 

Part of this difficult movement is thought by some to be 
caused by a mechanical adherence of the salts immediately 
in contact with the soil particles; others consider that an 
actual chemical reaction takes place. If no chemical 



110 CHEMICAL EQUILIBRIUM AND ANTAGONISM 

reaction occurs the salts held in a mechanical manner are 
probably within the inner circle of the capillary film where 
very little movement is possible; consequently, unless 
there is long-continued and excessive washing of the soil, 
little of this salt is lost except by diffusion which is a very 




Fig. 15. — Alkali Coming to the Surtace where Seepage Water 
FROM a Canal Comes to the Surface and Evaporates. The Canal 
Runs through a Shale that is High in Soluble Salts. 



slow process in case the salts are not promptly removed 
from the point of concentration. This adherence, or 
adsorption, may account for the great quantities of salts 
that are slowly yielded to water leaching through soils. 
As more and more of the salts are given up to the solution 
and carried away, the remaining portion is with greater 
and greater difficulty yielded to the free, or percolating, 
water. Because of the greater surface exposed, fine clays, 
loams, and soils rich in organic matter hold the salts by 
absorption more tenaciously than the coarser-grained sands. 
Soils such as the clays, which are high in colloidal ma- 
terial, are also affected by an interchange of ions. The 



EQUILIBRIUM IX SOIL SOLUTION 111 

colloidal material appears to be in weak, chemical com- 
bination with certain bases. When the alkah salts are 
brought in contact with these colloids, there is an apparent 
exchange of the sodium of the alkali for calcium or mag- 
nesium. The calcium and magnesium appear in the 
drainage water in ' greater quantities where the alkali is 
present than where it is not, and the sodium is recovered 
only with great difficulty if at all by leaching. This ac- 
tion is apparently selective in nature. The weaker acids 
yield their sodium to the colloids much more easily than 
do the stronger ones, so that where equal quantities of 
each of the salts are added to a soil when recovered the 
quantity of acid assignable to each base will be different. 
Each soil, and different parts of the same soil, frequently 
difTer considerably so that this interchange may vary both 
in nature and magnitude in soils not greatly differing from 
each other. The colloids of organic matter act much the 
same as those of the soil so that added organic matter may 
change the nature of an alkah soil. Whether it is due to 
tills exchanging of sodium for calcium in the colloids and 
the consequent precipitation of calcium carbonate when 
sodium carbonate is added to soils rich in colloids or in 
organic matter is not known, but much of the alkalinity 
of sodium carbonate disappears when added to such soils. 
In sand where colloids and organic matter are absent, 
practically all of the carbonates added can be recovered 
by extraction with water. 

Equilibrium in Soil Solution. — That a complete state 
of equilibrium is ever established in a soil is hardly probable. 
The constant removal of water by plants, evaporation 
from the surface of the soil, addition of water by rains or 
irrigation, percolation of free water, and all the other causes 
of movement of water in the soil, cause an incessant 



112 CHEMICAL EQUILIBRIUM AND ANTAGONISM 

change in the position of the soluble salts. Layers of 
compact soil or heavy clay ordinarily contain more soluble 
salts than looser ones; and where there is movement of 
water between different soil layers, there is a change in 
the concentration of the solution and reactions take place 
between the salts which have been dissolved from the two 
types of soil. Small quantities of alkali in the irrigation 
water may cause profound changes in the chemical com- 
position of the soil solution. Changes in temperature 
cause changes in the solubility of salts so that salts may be 
thrown out of solution or new ones brought into solution. 
Carbon dioxide and oxygen are frequently brought into 
the soil by rains, and carbon dioxide is constantly being 
formed in soils. This disturbs equilibrium of the com- 
pounds by changing the solubiht)^ or causing the oxidation 
of certain compounds. These and numerous other factors 
cause the soil solution constantly to vary in concentration 
and composition. 

Ifi studying alkali, however, these minute and trouble- 
some changes are not ordinarily of sufficient importance 
to warrant consideration. The quantity of alkali when 
it becomes troublesome is generally so large that small 
changes are practically negligible. Changing a few pounds 
to the acre of sodium chloride into calcium chloride would 
make so little difference in the toxicity of the alkali that 
it could not be noticed. 

With sodium carbonate the condition is somewhat dif- 
ferent. This salt is relatively unstable when compared 
with sodium chloride and sodium sulphate. In the pres- 
ence of solutions of carbon dioxide, as found in the upper 
soil, sodium carbonate would probably form the unstable 
sodium bicarbonate to a considerable extent. Sodium 
carbonate and bicarbonate, on account of their solubility, 



ANTAGONISM BETWEEN ALKALI SALTS 113 

react readily with other salts and may form the relatively 
insoluble carbonates. The well-known reaction Na2C03 
+ CaS04 = Na2S04 + CaCOs, or the conversion of black 
alkali into white, is of the latter type of change. Black 
alkali, however, is thought to remain practically in fairly 
stable equilibrium where the soil has become so puddled 
that air and carbon dioxide are largely excluded. Puddling 
the soil apparently causes the conversion of sodium nitrate 
into sodium carbonate w^here the conditions are favorable, 
but this reaction is rapidly brought to an end because of 
lack of sodium nitrate or the other agents under ordinary 
conditions. 

Antagonism between Alkali Salts. — In some of the early 
work of Kearney and Cameron (5) it was noticed that 
plants grown in solutions of single salts common in alkali 
soils showed a much greater tox,ic effect for magnesium 
sulphate and magnesium chloride than for the sodium salts 
which ordinarily cause the greatest trouble on alkaH land. 
When there were two salts, especially where one was a 
calcium salt, in the same solution, however, the toxic 
effect was not the sum of the two separate toxicities but 
was in some cases considerably less. Tliis ameliorating 
or antagonistic effect was shown differently for different 
combinations of salts and for different concentrations of 
the same combinations; but the greatest effect was for 
combinations containing calcijam and magnesium. The 
antagonism .between magnesium sulphate and calcium 
sulphate was particularly strong and led to the belief that 
a specific balance between calcium and magnesium must 
exist for proper growth of plants despite the fact that in 
soils such a relationship did not exist. Some of the 
ameliorating effect, such as that where calcium chloride 
and sodium carbonate were in the same solution, might 



114 CHEMICAL EQUILIBRIUM AND ANTAGONISM 

be assigned to the formation of new and less toxic com- 
pounds; but magnesium sulphate with sodium sulphate, 
sodium sulphate with magnesium chloride, sodium chloride 
with magnesium sulphate, and similar combinations which 
exist as stable compounds in contact with each other 
were also corrective of each other. It was further found 
that when the different salts were present in certain pro- 
portion to each other the effect was different than where 
other apparently less toxic proportions were used. When 
398 parts per million of sodium carbonate and 710 parts 
per million of sodium sulphate were in the same solution, 
some of the plants lived; but when the sodium sulphate 
was reduced to half this quantity, all the plants died. 

A number of other experimenters have noticed the 
antagonistic action between calcium and magnesium salts 
when in solutions with sodium salts. Miyake (16), work- 
ing with rice plants, found that there was a slight antago- 
nism between the monovalent anion, chloride, and the 
divalent anion, sulphate, but it was small compared with 
that between the cations. He found potassium antago- 
nistic to sodium when the two salts were together in the 
form of sulphates, chlorides, or nitrates. 

The quantity of salts which caused injury to the plants 
growing in the solutions of these experiments is much be- 
low the quantities ordinarily found to cause injury in field 
or soil experiments, especially where the unmixed solutions 
were used." It has been suggested that the reason for the 
lower toxicity in the soils is because the soil contains cal- 
cium and other salts which ameliorate the effect of the 
injurious salts. Whether this explanation is sufficient to 
account for all of the difference is questionable, however. 
That lime is a good corrective for magnesium, as reported 
above, is shown by the fact that certain Canadian soils (19) 



ANTAGONISM BETWEEN ALKALI SALTS 115 

containing 50,000 parts per million of magnesium suli^hate 
were made to produce much better growth by adding 
lime than without it. Most alkali soils contain consider- 
able lime. This may account for tlie large quantities of 
alkali sometimes present without serious injury to crops 
growing upon them. 

The work of Lipman and Gericke (11) indicates that 
even in a clay soil of the arid region there was antagonism 







Fig. 16. — Black Alkali Crust Forming where the Land 
HAS BEEN Wet. 

between sodium chloride and sodium sulphate, and be- 
tween sodium chloride and sodium carbonate in the second 
crop of barley, although none was shown in the first. 
That the time of contact might have had some effect is 
shown from the observation that neither sodium chloride 
nor sodium sulphate was stimulating in concentration of 
1000 parts per million for the first crop but were toxic 
for the second. Calcium sulphate was antagonistic even 
in comparatively small quantities when added to a soil 
containing 4000 parts per million of sodium sulphate. 

Lipman and Sharp (14), in an experiment with a natural 
soil containing 6400 parts per million of total salts com- 



116 CHEMICAL EQUILIBRIUM AND ANTAGONISM 

posed of 4590 parts per million sodium chloride, 980 parts 
per niillion sodium sulphate, and 830 parts per million of 
sodium carbonate, found that applying sulphuric acid at 
the rate of about 119 parts per million was especially bene- 
ficial, and up to about 451 parts per million, the highest 
quantity added, the treatment was beneficial. Gypsum 
also caused a higher yield of barley. The treatments were 
thought to be helpful both by neutralizing the sodium car- 
bonate and also by causing a beneficial shrinkage of colloids. 

A number of investigators have noted an antagonistic 
effect of the heavier metals, such as calcium, copper, and 
zinc, on the common alkali salts. Caldwell (i) thinks 
from his observations that this antagonistic efTect is due 
to a dilution of the active salts and not to an actual an- 
tagonism. He did not find an antagonistic action between 
sodium and potassium, but on the contrary he found a 
decrease in the stimulating effect when certain concentra- 
tions of potassium salts were diluted with sodium salts. 
Ammonia and sodium in the proportion of i to i gave the 
best growth in highly concentrated solutions. 

The author (3) found the antagonistic effect in solution 
cultures to be greater than when the same mixtures were 
present in soils. 

Some of the most positive antagonistic results in soils 
appear in the work of Lipman and his associates on soil 
bacteria. On the ammonification organisms he (9) found 
no antagonism between mangesium and calcium nor be- 
tween sodium and calcium, but there was an antagonistic 
effect both for these and the nitrifying organisms when any 
two of the three alkali salts — sodium chloride, sodium 
carbonate, and sodium sulphate — were in the soil together. 
There was antagonism between toxic as well as between 
stimulating concentrations of these salts. The nitrogen- 



REFERENCES 117 

transforming powers of the soil were better than the checks 
when two salts, one of which was present in toxic quantities, 
were present in the soil, or where both were in toxic 
quantities for the single salts. The nitrogen-fixing or- 
ganisms showed slight antagonism except between sodium 
sulphate and sodium carbonate which showed no 
antagonism. 

The exact cause of antagonism between the ions has 
not been fully explained. Osterhout (17) found the 
permeability of the protoplasm was rapidly increased until 
death occurred when in solutions of sodium chloride. 
With calcium chloride the permeability decreased to a 
certain point after which it increased as with sodium 
chloride until death occurred. He thinks that when a 
substance like sodium chloride is brought in contact with 
one like calcium chloride where the tendency is to cause 
permeability in opposite directions, there is an antag- 
onistic efTect. He (17) thinks this interference of the ions 
of the salts attempting to enter the cell may be the real 
cause of the antagonism. Hansteen (2) thinks calcium 
acts as an external protection to the roots of the plants, 
which is essentially that of the above view. Le Clerc and 
Breazeale (8) claim that lime overcomes the toxic effect 
of the sodium salts without preventing the absorption of 
sodium chloride by the plant. 

REFERENCES 

1. Caldwell, J. S. The Effect of Antaf^onistic or Balanced Solutions 

containing Sodium Chloride together with One of the Chlorides of 
Calcium, Magnesium, Potassium, Strontium, Ammonium, or Copper 
upon the Growth of Corn Plants Rooted in an Artificial Soil. Sci. 
n. ser. 39 (1914), P- 293. 

2. Hanstekn, B. The Relation of Plants to Certain Salts, I and II. 

Jahrb. wiss Bot. (Pringsheim), 47 (1910), No. 3. nn. 287-376. (Abs. 
E. S. R. 23, p. 328.) 



118 CHEMICAL EQUILIBRIUM AND ANTAGONISM 

3. Harris, F. S. Effect of Alkali Salts in Soils on the Germination and 

Growth of Crops. Jour. Agr. Res. 5 (1915), pp. i-53- 

4. JoFFA, M. B. Reaction between AlkaH Sulphates, Carbonates, and 

HCO3. Cal. Sta. Rpt. 1890, pp. 100-105. 

5. Kearney, T. H., and Cameron, F. K. Some Mutual Relations be- 

tween Alkali and Vegetation. U. S. D. A. Rpt. 71 (1902), 78 pp. 

6. Kelley, W. p. Action of Precipitated Magnesium Carbonate in 

Soils. Jour. Am. Soc. Agron. 9 (1917), pp. 285-297. 

7. Knight, H. G., and Moudy, R. B. Alkali Studies, VI. Wyo. Sta. 

Rpt. 1906, pp. 45-51. 

8. Le Clerc, J. A., and Breazeale, J. F. The Effect of Lime upon the 

Alkali Tolerance of Wheat Seedhngs. Orig. Commun. 8 Intn. 
Cong. Appl. Chem. (Washington and New York), 26 (1912), sect. 
Vla-XIb, App. p. 135. (Abs. E. S. R. 29, p. 322.) 

9. LiPMAN, C. B. Antagonism between Salts as Affecting Soil Bacteria. 

Sci. n. ser. 39 (1914), p. 764. See also Bot. Gaz. Vol. 49, p. 41. 

10. LiPMAN, C. B. Antagonism between Anions as Related to Nitrogen 

Transformation in Soils. The Plant World, 17 (1914), PP- 295-305. 

11. LiPMAN, C. B., and Gerick, W. F. Antagonism between Anions as 

Affecting Barley Yields on a Clay Adobe Soil. Jour. Agr. Res. 
4 (1915), pp. 201-218. 

12. LiPMAN, C. B., and Gerick, W. F. Copper and Zinc as Antagonistic 

to Alkali Salts in Soils. Am. Jour. Bot. 5 (1918), pp. 151-170. 

13. LiPMAN, C. B., and Burgess, P. S. Antagonism between Anions as 

Affecting Soil Bacteria, III. Nitrification. Centrbl. f. Bakt. Abt. 
42 (1914), Nos. 17, 18, pp. 502-509. (Abs. E. S. R. 33, p. 323.) 

14. LiPMAN, C. B., and Sharp, L. T. New Experiments on Alkali Soil 

Treatment. Univ. Cal. Pub. Agr. Sci. 9 (1915), No. 9, pp. 275- 
290. 

15. Marquenne, L., and Demoussy, E. The Influence of Salts on Vari- 

ous Metals on Germination in the Presence of Calcium. Comp. 
Rend. Acad. Sci. (Paris), 166 (1918), pp.'89-92. (Abs. E. S. R. 
39, p. 526.) 

16. MiYAKE,.K. Influence of the Salts Common in Alkali Soils upon the 

Growth of Rice Plants, I-IV. Bot. Mag. (Tokio), 27 (i9i3),pp. 173- 
182, 193-204, 224-233, 268-270 (Abs. E. S. R. 30, p. 630); Jour. 
Biol. Chem. 16 (1913), pp. 235-263 (Abs. E. S. R. 30, p. 833); 
Bot. Mag. Tokio, 28 (1914), pp. 1-4. 

17. OsTERHOUT, W. J. V. The Permeability of Protoplasm to Ions and 

the Theory of Antagonism. Sci. n. ser. 35 (1912), pp. 156-157. 

18. OsTERHOUT, W. J. V. Antagonism and Permeability. Sci. n. ser. 

45 (19.17), PP- 97-103- 

19. Shutt, F. T. Alkaline Soils of Canada. Can. Exp. Farms Rpt. 1893, 

PP- 135-140. 



CHAPTER IX 

RELATION OF ALKALI TO PHYSICAL 
CONDITIONS IN THE SOIL 

The entire physical condition of the soil is changed by 
the presence of large quantities of certain soluble salts. 
All salts in fact bring about some physical changes but 
certain of the alkali salts, particularly the carbonates, 
cause complete transformations. Each soluble salt that 
is present in large quantity produces some typical con- 
dition, which is usually bad. The effect of one salt may 
be in part neutralized by another, so that the final effect 
is somewhat uncertain. It depends on the nature of the 
soil and on the combination and concentration of the salts 
present. 

The chief manifestations of salts on the physical con- 
dition of the soil are: (i) The change in structure or tilth; 
(2) an altering of the colloidal substances; (3) the forma- 
tion of a hardpan; and (4) a change in the moisture re- 
lations. 

Changing Soil Structure. — The tilth, or structure, of a 
soil has much to do with its crop-producing power. Soils 
containing an equal amount of plant-food may vary 
greatly in their power to yield. The soil must do more 
than furnish a supply of food for growing plants; it must 
also be a good home for them. Plants, like animals, even 
though they have sufficient food to nourish them will not 
thrive unless other factors affecting growth are favorable. 
Air must be present for the roots, and the soil particles 

119 



120 RELATION TO PHYSICAL CONDITIONS 

should be so arranged that the roots may easily secure 
food and moisture. 

Soils vary greatly in their tilth. Those made up of 
coarse-grained particles are less affected in structure by 
various agencies than those composed of fine-grained 
particles. With coarse-grained soils the keeping of a good 
tilth presents no serious problem. With fine-grained soils, 
on the other hand, the maintaining of a good structure 
requires constant attention. It may be affected by several 
factors, one of which is the presence of soluble salts. 

The ideal structure is usually one in which there is a 
maximum of air space. This condition also favors the 
various cultural operations. If fine soil particles are 
packed tightly together, there is not sufficient air space 
for the best root development and the soil is difficult to 
till. When plowed, it becomes cloddy instead of mellow. 
In order to secure the best condition, the fine particles 
should be clustered together, or flocculated. This gives 
air space between the groups of particles as well as be- 
tween the individual particles in the group and establishes 
lines of weakness in all directions. This enables the soil 
to break up readily into a crumb-like structure when cul- 
tivated instead of into clods. Anything that promotes 
flocculation improves tilth; likewise anything that pro- 
motes deflocculation injures tilth. 

The effect of soluble salts on tilth has been a subject of 
considerable study. Sachsse and Becker (17) showed that 
nitrate of soda not only prevented flocculation but also 
separated floccules that had already been formed. It 
was thought that this result might be due in part to the 
formation in the soil of carbonate of soda, which in turn 
acts upon the hydrated silicates, producing colloidal sili- 
cates which reduce the permeability of the soil to water. 



CHANGING SOIL STRUCTURE 121 

Hall (lo) found that when nitrate of soda was applied in 
large quantities to heavy soils at Rothamsted the tilth 
of the land was destroyed. He concluded that this result 
came about by the production of the defiocculating salt, 
sodium carbonate. 

The presence of alkali salts was early observed by 
Loughridge (15) and Hilgard (13) to have a bad effect 
on the soil by puddling or deflocculating the particles 
and a consequent compact condition which prevents the 
rapid rise of water. Puddling was accompanied by large 
contraction of volume. A similar action particularly in 
clays was also observed by Bemmeln (i). 

Masoni (16) showed that not all soluble salts have a 
defiocculating efTect. Some of them have a decidedly 
flocculating effect which is not dependent on the quantity 
of salt but rather on ionic concentration and the degree 
of dissociation. He considers the flocculating power to 
be a function of the cation, the anion being without in- 
fluence. If the value of the flocculating power ^r the 
sodium ion be taken as i, then for the potassium or am- 
monium it is 2.4, and for the calcium ion 5.7. 

Free (7) has pointed out that flocculation and defloccula- 
tion are relative terms and that the action of salts, acids, 
and alkalies in this connection are twofold and depend 
on the mutual interpenetration of particle and medium 
and on the electrical charge on the surface of the particle. 

Davis (6) has shown that even small quantities of soluble 
salts are important in modifying the physical properties 
of the soil including the apparent specific gravity which is 
affected directly by the flocculation of the particles. The 
effect of salts is shown to be very much greater in soils of 
finer particles than in sands. It is usually in the finer, 
heavier soils that alkali is found; consequently, it is usually 
only in these soils that the problem becomes troublesome. 



122 RELATION TO PHYSICAL CONDITIONS 

The acute form of defiocculation manifests itself in the 
crust at the surface of the soil resulting from sodium car- 
bonate or black alkali. Only slightly less troublesome is 
the brown crust found where large quantities of sodium 
nitrate are present. Where these crusts are found it be- 
comes almost impossible to raise crops successfully. Not 
only is the land difficult to till but the crust that may 
form after a tender plant comes up is so hard that the 
plant cannot make a normal growth. There is an actual 
physical impediment in addition to any chemical corroding 
which the salt may exert on the plant. 

Effect of Colloids. — All agricultural soils contain some 
particks called colloids so small that they have properties 
entirely different from the larger particles. The colloidal 
material acts somewhat like dissolved salts and yet it 
obeys some of the laws that apply to the larger particles. 
During recent years it is being recognized that many of 
the effects of alkalies on the physical conditions of soils 
come about through this colloidal material. 

Kellerman (12) showed that the impermeable condition 
of an alkah soil at Fallon, Nevada, was due largely to the 
condition of the colloidal matter in the soil. 

Gedroits (9), as a result of extensive experiments on the 
relation of salts to soil colloids, found that many of the 
physical changes ordinarily brought about in soils by 
salts come from their effect on colloids. 

Important as are the investigations already made on 
the relation between alkali and soil colloids, they may be 
considered as only pioneer work in view of what the future 
promises. 

Hardpan. — Under the surface of many of the soils in 
arid regions, particularly in sections of abundant alkali, a 
hard layer is found which obstructs the penetration of 



HARDPAN 123 

both roots and water. Hardpans arc not always caused 
by alkali, but are more likely to be formed if it is present. 
Hardpan differs from the ordinary impervious subsoil in 
that it has a limited thickness, usually varying from 2 to 
18 inches with an average of 3 to 6 inches. A good ex- 
ample is described by Gardner and Stewart (8). A num- 
ber of explanations of the genesis of hardpans have been 
given. 

Hilgard (13) has the following to say about the cause of 
hardpan: "The recognition of the cause of hardpan is of 
considerable importance to the farmer because of the in- 
fluence of the nature of the cement and the causes of its 
formation upon the possibility and methods of its de- 
struction, for the improvement of the land. 

*'It may be said in general that inasmuch as the cause 
of the formation of hardpan is a stoppage of the water in 
its downward penetration, the reestablishment of that pene- 
tration will tend to prevent additional induration; more- 
over, experience proves that whenever this is accomplished 
even locally, as around a- fruit tree in an orchard, the hard- 
pan gradually softens and disappears before the frequent 
changes in moisture conditions and the attack of roots. 
The use of dynamite for this purpose in California has 
already been referred to; it seems to be the only resort 
when the hardpan lies at a considerable depth. When it 
is within reach of the plow, it may be turned up on the 
surface by the aid of a subsoiler and will then gradually 
disintegrate under the influence of air, rain, and sun. 
But when the hardpan is of the nature of moorbedpan, 
containing much humic acid and perhaps underlaid by 
bog-iron ore, the use of lime on the land is indicated, and 
will in the course of time destroy the hardpan layer. This 
is the more desirable as in such cases the surface soil is 



124 RELATION TO PHYSICAL CONDITIONS 

usually completely leached of its lime content, and is con- 
sequently extremely unthrifty." 

Cameron (5) gives the following explanation of the origin 
of hardpans: "The application of the present views re- 
garding solutions to the study of hardpan phenomena gives 
promise of valuable as well as interesting results. A hard- 
pan may be defined as a layer of the soil, usually near the 
surface, having the texture of the soil just above and below 
it, but more or less closely cemented by some material. 
In general, hardpan is a characteristic of soils where drain- 
age is very poor or where standing soil waters may ac- 
cumulate. The cementing material is often lime carbonate, 
but may be other material, as the hydrates of iron and 
alumina or sihca. Hardpans vary much in their physical 
properties. They are sometimes as dense and close- 
grained as a well-characterized rock, requiring blasting or 
similar methods to break them up. In other cases they 
may be partly porous, and when brought to the surface 
disintegrated with ease, and there are all grades between 
these extremes. 

"The objections to their presence in the soil are evident. 
They prevent the penetration of plant roots, and, more 
important, they prevent the moisture from rain, irriga- 
tion, etc., sinking into the soil and thus being conserved for 
future use. They also prevent the water that may be 
beneath them from being drawn to the surface and made 
available for the plants. 

"The formation of a calcium carbonate hardpan is the 
most readily understood, and this has been dwelt upon at 
some length in a paper by Gardner and Stewart (8). It 
is there pointed out that resolution and repirecipitation 
are important factors. But when the calcium carbonate 
does not exist, as such, in the soil or in the vicinity, so as 



HARDPAN 125 

to be brought by water, vvliile a limestone hardpan might 
form, under favorable conditions, it seems more prol^able 
that the cementing material would be one of the other 
substances mentioned, or a mixture of them. 

''The mineral constituents of the soil arc for the most 
part salts, but with a few exceptions salts with a very- 
limited solubility. Nevertheless, to some extent at least 
they are soluble, as are other salts, and their solubility 
may be increased or diminished by the presence of another 
salt solute, as has been indicated in a former part of this 
paper. These salts — carbonates, silicates, aluminates, 
ferrates, etc. — are without exception salts of weak acids 
and may be expected to be much hydrolized in as far as 
they are soluble at all. This has been very beautifully 
illustrated in recent experiments by Clark, who has treated 
a large number of minerals carefully pulverized with pure 
water. On the addition of a few drops of dilute alcoholic 
phenolphthalein a marked alkaline reaction could be ob- 
served in the great majority of the cases investigated. 
The reaction may be indicated thus, assuming a very 
simple example to exist: 

RSiOs + HOH^ROH + H2Si03. 

"All these other substances are very slightly ionized 
in comparison with ROH. If R be a well-marked base, 
such as sodium or calcium, the solution will therefore be 
alkahne, as has been shown to be the case with calcium 
carbonates, sodium silicates, etc. The fact that the 
silicate is complex will not alter this general property. 
Precisely similar conduct is to be expected of aluminates 
and ferrates. This means that there will actually exist 
in the solution some of the hydrates of alumina, silica, or 
iron, as the case may be, which w'ill remain as such on 
evaporation, though the absolute amount may be very 



126 RELATION TO PHYSICAL CONDITIONS 

small. The bases will be more or less readily removed, as 
they will be brought in contact with the carbonic acid and 
other acids (organic?) of the soil to form comparatively 
readily soluble salts. 

"This process probably plays an important part in the 
formation of bog-iron ore, which may be regarded as 
strictly analogous to a hardpan. The deposition of 
bauxite, for example, or the formation of a silicious con- 
glomerate is essentially of the same nature. But it should 
be remembered that in these latter cases when the action 
has been deep-seated with hot water as the solvent, the 
reagent has been much more ionized and so is much more 
efficient as a solvent. 

''An interesting case from southern California has re- 
cently come to our attention. The soil was shown to have 
been somewhat compacted under the plow sole. When 
the irrigating water was applied, this packed region of the 
soil caused a more or less temporary accumulation of the 
waters. This soil, as can be readily seen under the micro- 
scope, contains a large proportion of unaltered mineral 
fragments, rich in iron and alumina and therefore well 
adapted to yielding these materials under the influence 
of the solvent action of the water; and, as a matter of 
fact, this packed material is found to rapidly become 
cemented with iron and alumina, as an examination in 
this laboratory showed. It is to be regretted that at the 
time this examination was in progress it was not deemed 
expedient to determine what constituents the irrigating 
water held which might augment its solvent power. 

"That other agencies are at work in the production of 
these phenomena may well be the case. For instance, 
oxidations undoubtedly have a significant role in this 
connection in breaking up the original minerals. But it 



HARD PAN 



127 



seems equally certain that the part that solutions play has 
not been given the consideration that it merits, mainly 
because solution i)henomena have not been understood 
until comparatively recent years. 

"The study of hardpan formation necessitates a con- 
sideration of certain physical phenomena; for instance, 
the movement of water and various solutions in the soil. 
This subject is receiving attention in this laboratory; but 
while a good many observations have been made and much 
valuable data collected, it is yet too soon to formulate a 
complete hypothesis for this subject. The views here 
described are put forward in the hope of furnishing an in- 
centive to more widespread interest and work on this 
important subject," 

Heileman (12) gives in Table XVI the composition of a 
t}pical hardpan in the Kittitas Valley, Washington. 
Table XVI. Composition of Hardpan 





Total Lime and Magnesium Carbonate 
IN Hardpan 


Water-soluble Salts 


[N Hardpan 




Calcium Carbonate, 
Per cent 


Magnesium Carbonate, 
Per cent 


Total Salts 
Per cent 


Black Alkali 
Per cent 


White Alkali 
Per cent 


No. 8 
21 
46 
56 


21.15 

14-93 
21.79 
63.22 


1.72 

3 09 
2.97 

2-45 


■343 
.136 
■133 
•350 


.174 
.029 
.109 
■145 


.018 
.023 
.Oil 

.041 



Breazeale (2) shows that the idea that hardpan under a 
soil high in sodium carbonate has resulted from the sodium 
carbonate may not be true. In fact the sodium carbonate 
accumulation may have come from a decomposition of the 
calcium carbonate in the hardpan and a combination with 
sodium to form the black alkali. He succeeded in bringing 
about this interchange in the laboratory. 



128 RELATION TO PHYSICAL CONDITIONS 

Effect on Moisture Movements. — The somewhat un- 
usual moisture conditions in alkali soils have long been 
observed by students of alkali. Briggs and Lapham (4) 
investigated the effect of various soluble salts on rate of 
capillary movements through the soil and as a result of 
their studies came to the following conclusions: "(i) Dis- 
solved salts in general do not increase the capillary rise of 
soil waters; (2) neutral salts in dilute solution have prac- 
tically no influence on the extent of capillary action; 
(3) concentrated or saturated solutions of all salts materially 
diminish capillary activity; (4) this effect appears to be 
due (a) to the increased density of the solution which 
more than offsets the increased surface tension, and (b) to 
the resistance of a film to a tangential shearing stress which 
retards capillary action and offers in addition a permanent 
resistance to the movement of the solution through films, 
thus increasing the angle of contact, or (e) to an increase 
in the tension of the liquid-solid surface, as the concen- 
tration is increased; (5) sodium carbonate differs from 
neutral salts, the capillary rise being considerably greater 
than for neutral solutions of equal concentration; (6) this 
may be due in part to the saponification of traces of grease 
on the surface of the soil grains through the hydrolysis 
of the sodium carbonate, thus forming clean surfaces for 
capillary action; (7) the same effect should consequently 
be observed with all salts which undergo an alkaline hy- 
drolysis, viz., potassium and sodium carbonates, borates, 
phosphates, etc. ; (8) this action is characterized in the soil 
tubes by indistinctness of the upper boundary of the 
capillary column." 

Capillarity is dependent on surface tension. Since the 
capillarity does not seem to be greatly influenced by 
soluble salts it seems evident, as pointed out by Davis (6), 



EFFECT ON MOISTURE MOVEMENTS 129 

that the profound physical changes brought about in the 
soil by alkah arc due largely to forces other than surface 
tension. This is illustrated by the fact that while in the 
experiments of Briggs and Lapham (4) sodium carbonate 
increased the capillary rise of water, it is a well-known fact 
in field practice that the presence of large quantities of 
sodium carbonate, or black alkali, interfere with the pas- 
sage of water through the soil. In an experiment con- 
ducted by the author, there was added to a fertile loam 
soil 5 per cent of sodium carbonate. The soil was then 
placed loosely in percolators so that the total depth of 
soil was four feet. The same soil containing no sodium 
carbonate was arranged in similar manner. Water was 
then added to each soil and kept six inches deep over the 
surface. In the normal soil the water percolated through 
the four-foot column in two hours, whereas it failed to 
penetrate the four feet containing carbonate in a year. 
The organic matter was dissolved from the upper layer 
and washed to a lower level where it made the soil im- 
penetrable. 

Excessive nitrates in the soil act in much the same way 
as the carbonates except that the crust they form has a 
brown, instead of a black, color and it is not so im- 
penetrable. The nitrates also interfere much less with 
the passage of water. Alkali spots are often found where 
the soil remains permanently dry several inches below the 
surface even though irrigation water is run over them 
every week for several months. It is very evident there- 
fore that though the salts may not exert a strong influence 
of direct capillary action they do ver>' materially afYect 
the absorption of irrigation and rain water in practice. 

Where gypsum is present in large quantities in an ir- 
rigated soil, it is gradually washed out, causing the soil to 



130 RELATION TO PHYSICAL CONDITIONS 

sink and leave typical holes. Sodium and magnesium 
chlorides and sulphates have less marked, but very dis- 
tinct, effects on moisture movements. 

Evaporation of Moisture. — The vapor tension of water 
is reduced by the presence of dissolved salts; hence the 
presence of alkali reduces the rate of evaporation. The 
rate of decrease of evaporation produced by the various 
salts is shown by Briggs (3) and by Harris and Robin- 
son (11). It is not equal to the reduction in the vapor 
tension of the solution since the air at all times contains 
some moisture. The results of Harris and Robinson 
showed an evaporation of 190 grams from distilled water 
and only 100 grams from an equal surface of water in which 
had been dissolved 30 per cent of sodium chloride. Sand 
moistened with distilled water had a loss of 80 grams, 
whereas that with a 2-normal solution of sodium nitrate 
evaporated but 53 grams of water. 

In an experiment by the author a loam soil, to which 
had been added various quantities of the sodium chloride, 
sodium sulphate, and sodium carbonate, was placed in 
petri dishes in a closed chamber in which the air was kept 
saturated. The soils all took moisture from the air, the 
rate of absorption depending on the salt and the concen- 
tration. In the higher concentrations so much moisture 
was absorbed that free water covered the surface of the 
soil. A condition similar to this is often found in nature 
where the soil of an alkali spot is wet constantly during 
the season even though the surrounding soil is dry. 

REFERENCES 

, I. Bemmeln, J. M. VON. On the Plasticity of Clay Soils. Chem. 
Weekbl. 7 (1910), pp. 793-805. 
2. Breazeale, J. F. Formation of Black Alkali (Sodium Carbonate) 
in Calcareous Soils. Jour. Agr. Rsch. 10 (1917), PP- 541-589- 



REFERENCES 131 

3. Briogs, L. J. Salts as liilluL-m in^' tlu' Kale of I'>vai)<>ration of water 

from Soils. U. S. I). A. Hur. of Soils, Kpt. 64 (iSqi)), pp. 184-198. 

4. Brioc.s, L. J., and Lapham, M. II. Inlhicncc of Dissolved Salts on 

the Caiiillary Rise of Soil Water. U. S. I). A. Hur. Soils, Ikil. 19 
(1902), 18 pp. 

5. Cameron, F. K. Application of the Theory of Solution to the Study 

of Soils. U. S. D. A. Bur. Soils, Rpt. 64 (1899), pp. 141-172. 

6. Davis, R. O. E. The Effect of Soluble Salts on the Physical Properties 

of Soils. U. S. D. A. Bur. Soils, Bui. 82 (191 1), 38 pp. 

7. Free, E. E. The Phenomena of Flocculation and Deflocculation. 

Jour. Franklin Inst. 169 (1910), pp. 421-438, and 170 (1911), pp. 46- 

57- 

8. Gardner, F. D., and Stewart, John. A Soil Survey of Salt Lake 

Valley, Utah. U. S. D. A. Bur. of Soils, Rpt. 64 (1899), pp. 77-114. 

9. Gedroits, K. K. Colloid Chemistry in the Study of Soils. Zhur. 

Opytn. Agron. (Russ. Jour. Exp. Landw.), 13 (1912), pp. 363-420. 
(Abs. E. S. R. 28, p. 516.) 

10. Hall, A. D. Some Secondary Action of Manures upon the Soil, 

Jour. Roy. Agr. Soc. (England), 70 (1909), pp. 12-35. (Abs. E..S. R. 
23, p. 320.) 

11. Harris, F. S., and Robinson, J. S. Factors afTecting the Evaporation 

of Moisture from the Soil. Jour. Agr. Rsch. 7 (1916), pp. 439-461. 

12. Heileman, W. H. Alkali and Alkali Soils. Wash. Sta. Bui. 49 (1901), 

35 PP- 

13. HiLGARD, E. W. Soils, pp. 183-187. (New York, 1906.) 

14. Kellerman, K. F. The Relation of Colloidal Silica to Certain Im- 

permeable Soils. Sci. n. ser. 33 (191 1), pp. 189-190. 

15. LouGHRiDGE, R. H. Investigations in Soil Physics. Cal. Sta. Rpt. 

1893-94, pp. 70-100. 

16. Masoni, G. The Flocculating Power of Some Soluble Salts on Clay 

Substances of the Soil. Spaz. Sper. Agr. Ital. 45 (1912), pp. 113- 
159. (Abs. E. S. R. 27, p. 620.) 

17. Sacchase, R., and Becker, A. The Influence of Lime and Salts, as 

well as Certain Acids, on the Flocculation of Clay. Landw. vers. 
Stat. 43 (1893), pp. 15-25- (Abs. E. S. R. 5, p. 696.) 

18. Sharp, L. T. Fundamental Relationships between Certain Soluble 

Salts and Soil Colloids. Univ. Cal. Pub. .Agr. Sci. i (igi6), No. 10, 
pp. 291-339; also see Proc. Nat. Acad. Sci. i (1913), pp. 563-568. 



CHAPTER X 

RELATION OF ALKALI TO BIOLOGICAL 
CONDITIONS IN THE SOIL 

The effect of soil alkali in reducing the growth of crops 
or in changing completely the type of native vegetation is 
easily recognized. There are, however, equally as im- 
portant changes produced in the microorganisms. These 
changes cannot be detected without special study of a 
technical nature and are therefore not so well understood. 
The micro-flora of the soil is probably as varied and as 
complex as the plant growth on the surface, but the re- 
sponse of these smaller organisms has not been as thoroughly 
studied as that of the higher plants. However, a few 
rather definite facts have been estabhshed. 

Relation of Soil Organisms to Fertility. — It has long 
been known that bacteria and fungi in the soil are essential 
to continued growth of the higher plants. The constant 
tearing down of dead organic matter furnishes new material 
for assimilation by living plants. Most plants require 
nitrogen in the form of either ammonium salts or nitrate 
nitrogen. One of the important sources of such salts is 
vegetable matter of the soil which has been reduced to 
the proper form by decomposition. Certain microorgan- 
isms attack and break up the complex organic tissues of 
plants as soon as their resistance has been decreased by 
death or otherwise. Different organisms act on the dif- 
ferent compounds as decomposition proceeds until the 
material is finally reduced to the simple compounds such 

132 



SOIL STERILITY 133 

as are required by plants. Fungi and putrefying bacteria 
reduce the vegetable proteins to a form which can be acted 
upon by the ammonifying bacteria which finally leave the 
nitrogen in the form of ammonia; it may then be either 
combined into an ammonium salt and utilized by the 
plant or oxidized by other organisms into nitrous, and 
then nitric, acid. The latter combines with bases in the 
soil to form nitrates. Where the proper organisms are 
in the soil in sufficient numbers to carry this process 
smoothly to a finish the soil is usually highly productive. 

Desirable organisms other than of the class mentioned 
above are the symbiotic nitrogen-fixing bacteria which 
Vive in the nodules of legume roots and synthesize at- 
mospheric nitrogen into forms which can be utilized by 
the host plant. A number of diflferent kinds of bacteria 
fix atmospheric nitrogen without symbiosis with higher 
plants; still other organisms are known to break up and 
make available certain insoluble compounds in the soil 
which are essential to profitable crop production. 

The desirable microorganisms do best under practically 
the same soil conditions as do crop plants. They thrive 
or grow most luxuriantly in soils rich in organic matter, 
well aerated, and with about the optimum moisture content 
for most crops. Where the soil is water-logged, puddled, 
or contains injurious matter, the more desirable nitrify- 
ing and nitrogen-fixing bacteria are largely replaced by 
denitrifying and putrefying organisms which rapidly 
deplete the soil of available nitrogen. 

Biological Inactivity and Soil Sterility. — Alkali salts 
which injure or prevent the production of crops on certain 
lands also injure the activities of the desirable soil organ- 
isms. Taylor (i8) found that at least part of the sterility 
of certain Bengal soils was due to scarcity of bacteria and 



134 BIOLOGICAL CONDITIONS OF THE SOIL 

nitrogen. Some soil students go so far as to say that an 
important part of the injury to crop production on alkali 
lands is due to decreased bacterial activity. They hold 
that this is shown by the fact that crop yields do not 
always decrease to the full extent when alkali is first brought 
in contact with the soil, but continue to decrease as time 
allows the microorganisms to die gradually. They also 
point out that soils do not become at once productive after 
being drained of alkali, but gradually increase in productive- 
ness as the desirable organisms are given time to multiply. 
Whether the changes which soils undergo subsequent to 
drainage are due largely to bacterial activities or almost 
wholly to physiological changes is not at present known. 

From preliminary experiments by Lipman and 
Fowler (13) in which soils were treated with 500 parts per 
million of sodium carbonate, 1000 parts per million of 
sodium chloride, 2500 parts per milhon of sodium sulphate 
and mixed salts, and then leached free of the salts, it was 
found that nitrification was affected profoundly by the 
leaching. The characteristic effects of the salts on the 
organisms remained after the salts had been almost en- 
tirely leached out. The soil receiving the mLxed salts 
was most toxic, with sodium carbonate, sodium chloride, 
and sodium sulphate in the order named. This same action 
was noted for the nitrogen-iixing bacteria, although it 
was not so characteristic as with the nitrifying ones. The 
results with the ammonifiers was not so distinctive. 

Barnes and Ali (i) found that the ammonifying bac- 
teria, and to a less extent the nitrifiers, might be used to 
measure the toxicity of the alkali or its crop-producing 
power much more quickly and at less expense than by 
growing crops. They believe that the alkah merely causes 
the organism to lie dormant until favorable conditions 



LIMITS OF TOXICITY \^5 

again prevail. By determining the ammonifying, nitrify- 
ing, and nitrogen-fixing power of the organisms they pro- 
pose to classify land that is being drained as to its ability 
to grow crops. 

Concentrations of Alkali which Limit Biological Ac- 
tivities. — The quantity of alkaU that will cause injury 
to the ammonifjing and nitrifying bacteria as determined 
by different investigators varies from a minimum of 250 
parts per million of sodium carbonate, which was found 
by Lipman (10) to inhibit growth of these organisms, to 
a maximum of 4000 parts per million of this salt as found 
by Kelley (8) . The nature and concentration of the nitrog- 
enous material used to determine the activity of the or- 
ganisms has been found to make a great difference in the 
rate of nitrification. Kelley found that where i per 
cent of dried blood was used as the nitrogenous material, 
500 parts per million of sodium carbonate was distinctly 
toxic, but where only 0,1 per cent of dried blood was used 
the organisms were apparently not affected by the presence 
of 4000 parts per million of sodium carbonate. He also 
found that while 1000 parts per million of sodium car- 
bonate were toxic to nitrification in the presence of 0.15 
per cent of ammonium sulphate, this concentration was 
markedly stimulating in the presence of 0.0625 per cent of 
ammonium sulphate. The large discrepancies in the 
quantities of alkali which these bacteria withstand are 
probabl}' due in part to the differing quantities and kinds 
of nitrifying materials used as well as the kind and dif- 
fering natures of the soils. Dried blood, cottonseed meal, 
ammonium sulphate, and numerous other materials have 
been used; this makes comparisons of the different ex- 
periments diflficult. Standard methods are needed in this 
regard as they are in other alkali work. It is probable 



136 BIOLOGICAL CONDITIONS OF THE SOIL 

that absorption of the sodium carbonate by the organic 
matter of the soil plays a considerable part in these ex- 
periments, as the salts were added to the soil, and, as 
mentioned in Chapter V, loam soils, especially those high 
in organic matter, do not hold in solution all of the sodium 
carbonate added. 

The various experiments agree pretty well that about 
looo parts per million of sodium chloride is a toxic quantity. 
Greaves, Carter, and Goldthorpe (6) found a stimulation 
with this salt up to a concentration of about looo parts 
per million above which there was a marked toxicity 
Other investigators have found stimulation where the 
quantities of sodium chloride were lower than this. 

From the available experiments, the toxic limits of 
sodium sulphate appear to lie between 2500 and 5000 
parts per million. Small quantities of this salt were found 
to be stimulating to nitrifying bacteria by Brown and 
Hitchcock (2), but Greaves and his associates (6) found 
no stimulation even in soils containing very small quanti- 
ties of sodium sulphate. 

Greaves found the toxic limits for sodium nitrate to be 
only a little greater than 200 parts per million, or much 
more toxic in comparison with its toxicity to wheat than 
are the other sodium salts. The quantities of sodium 
carbonate, sodium chloride, and sodium sulphate present 
in soils producing half the quantity of dry matter of normal 
wheat plants and those in soils producing half-normal 
nitrification were found to be nearly the same. The 
salts which stimulated wheat most also stimulated nitri- 
fying bacteria. 

From the low quantities of sodium carbonate and sodium 
nitrate which cause injury to nitrifying bacteria, it appears 
that the puddling effect of these salts may play an im- 



LIMITS OF TOXICITY 137 

portant part in their toxicity. In Colorado (17), however, 
soils containing rather large quantities of nitrates were 
found to be still active in nitrif)ing, although when the 
nitrates became excessive the organisms were destroyed 
or greatly checked in their activity. 

Kelley (8) found that the nitrite-forming organisms 
were still active in soil containing so much alkali that 
nitrate formation had practically ceased. 

Nitrogen-fixing organisms were found by Lipman and 
Sharp (14) to be inhibited by the presence of 4000 to 5000 
parts per million of sodium carbonate. The toxic limits 
for sodium chloride were 5000 to 6000 parts per million, 
and for sulphate about 12,500 parts per million. Much 
smaller quantities were found injurious where the soil was 
leached of its salts, the quantity in this experiment being 
nearly the same as with the nitrifying bacteria (13). 

Hills (7) reports that 1500 parts per million of sodium 
nitrate stopped multiplication and probably killed many of 
the nitrogen-assimilating organisms. Symbiotic bac- 
teria (15) on peas were retarded in their activities when 
sodium salts in cultural solutions with a strength of ;^t,^t, 
parts per million were used. Alkaline nitrates at a con- 
centration of 100 parts per million and ammonium salts 
at a concentration of 500 parts per million checked the 
production of root tubercles. 

Ammonification organisms have been found by investi- 
gators who have experimented with them in comparison 
with those concerned with nitrification and nitrogen- 
fixation to be more tolerant of alkali than these other 
nitrogen-working organisms. Lipman found the toxic 
points for ammonification to be at 20,000 parts per 
million of sodium carbonate, 1000 to 2000 parts per 
million of sodium chloride, and 4000 parts per million 



138 BIOLOGICAL CONDITIONS OF THE SOIL 

of sodium sulphate. For one-half normal ammonifying 
power, Greaves found the points to be at ii,66o parts 
per million of sodium carbonate, 1170 parts per million of 
sodium chloride, and 8520 parts per miUion of sodium 
sulphate. The results of Brown and Johnson (3) indicate 
a lower limit, but all show that sodium chloride is the most 
toxic. The relationship of the three salts is nearly re- 
versed to that in their action on plants. Greaves (5) found 
sodium nitrate to be toxic at about 426 parts per million. 
He noticed a stimulating effect of sodium carbonate, 
sodium nitrate, and sodium chloride in decreasing order 
when only small quantities of these salts were present, 
but found none with sodium sulphate. His experiment 
also showed that some salts increase in toxicity with in- 
creasing quantities of salts much faster than others. 

Lipman (9) noticed antagonism between the anions of 
the sodium salts, the action being strongest betweeji 7000 
parts per million sodium carbonate and 2000 parts per 
milHon sodium chloride, next between sodium carbonate 
and sodium sulphate, and weakest between sodium chlo- 
ride and sodium sulphate. Antagonism was noted '^ be- 
tween toxic and stimulating salts as well as between two 
toxic salts." A reduction of the stimulating effect of 
sodium carbonate on ammonification was noticed by 
Brown and Johnson (3) when calcium carbonate was added 
to the soil, but the toxic effect was also reduced. Both 
sodium chloride and sodium sulphate showed more stimu- 
lation and certain toxic quantities became stimulating 
when calcium carbonate was added. "Combinations of 
various salts in non-toxic individual amounts in the pres- 
ence of calcium carbonate became toxic to ammonification." 

Other soil organisms have been little studied. Hun- 
ter's (16) experiments show that Actinomycetes were 



REFERENCES 139 

stimulated by the addition of 50,000 parts per million of 
potassium chloride or sodium chloride, but that spore 
formation was decreased, while 100,000 parts per million 
usually arrested development. 



REFERENCES 

1. Barnes, J. H., and Ali, Barkat. Alkali Soils: Some Biochemical 

Factors in their Reclamation. Agr. Jour. India, 12 (1917), pp. 368- 
389.. (Abs. E. S. R. 38, p. 815.) 

2. Brown, P. E., and Hitchcock, E. B. The Effects of Alkali Salts on 

Nitrification. Soil Sci. 4 (1917), pp. 207-229. 

3. Brown, P. E., and Johnson, D. R. Effects of Certain Alkali Salts 

on Nitrification. Iowa Sta. Res. Bui. 44 (1918), 24 pp. 

4. Greaves, J. E. Azofication. Soil Sci. 6 (1918), pp. 163-217. 

5. Greaves, J. E. The Influence of Salts on the Bacterial Activities of 

the Soil. Soil Sci. 2 (1916), pp. 443-480. 

6. Greaves, J. E., C.a.rter, E. G., and Goldthorpe, H. C. Influence 

of Salts on the Nitric-nitrogen Assimilation. Jour. Agr. Res. 16 
(1919), pp. 107-135. 

7. Hills, T. L. Influence of Nitrates on Nitrogen Assimilation. Jour. 

Agr. Res. 12 (1918), pp. 183-230. 

8. Kelley, W. p. Nitrification in Semiarid Soils. Jour. Agr. Res. 7 

(1910), pp. 417-437- 

9. LiPMAN, C. B. Antagonism between Anions as Affecting Ammoni- 

fication in Soils. Centbl. f. Bakt. Abt. 2, Bd. 36 (1913), pp. 382- 

394- 

10. LiPMAN, C. B. To.xic Effects of Alkali Salts in Soils on Soil Bacteria. 

II. Nitrification. Centbl. 1. Bakt. Abt. 2, Bd. 3,3 (1912), 

PP- 305-313- 

11. LiPMAN, C. B. To.xic Effects of .\lkali Salts on Soil Bacteria. I. Am- 

monification. Centbl. f. Bakt. Abt. 2, Bd. 32 (1911), pp. 58-64. 

12. LiPMAN, C. B., Burgess, P. S., and Klein, M. A. Comparison of the 

Nitrifying Powers of Some Humid and Some Arid Soils. Jour. 
Agr. Res. 7 (1916), pp. 47-82. 

13. LiPMAN, C. B., and Fowler, T. W. Preliminary Experiments of Some 

Effects of Leaching on Soil Flora. Soil Sci. i (1916), pp. 291-297. 

14. LiPMAN, C. B., and Sharp, L. T. Toxic Effects of Alkali Salts in Soils 

on Soil Bacteria. III. Nitrogen Fixation. Centbl. f. Bakt. Abt. 
2, Bd. 35 (1912), pp. 647-655. 



140 BIOLOGICAL CONDITIONS OF THE SOIL 

15. Marchal, E. Influence of Mineral Salts on the Production of Tuber- 

cles on Pea Roots. Compt. Rend. Acad. Sci. (Paris), 133 (1901), 
pp. 1032-1033. (Abs. E. S. R. 13, p. 1017.) 

16. MuNTER, E. The Influence of Inorganic Salts on the Development of 

Actinomycetes, III. Centbl. f. Bakt. 2 Abt. Bd. 44 (1916). pp. 673- 

695- 

17. Sackett, W. G. Bacteriological Studies of the Fixation of the Nitro- 

gen in Certain Colorado Soils. Colo. Sta. Bui. 179 (191 1). 

18. Taylor, C. S. Effect of Salts on Soils. Dept. Agr. (Bengal), Quart. 

Jour. 2 (1909), pp. 281-287. (Abs. E. S. R. 22, p. 124.) 



CHAPTER XI 

MOVEMENT OF SOLUBLE SALTS THROUGH 
THE SOIL 

The greatest problem connected with the utilization of 
alkali lands is control of the movement of soluble salts. 
Were it possible to handle the land economically so that 
the movement of the alkali would be continually down- 
ward into the subsoil, or better, into the drainage system 
where it would be permanently removed from the feeding 
zone of the plants, the alkali problem would be solved. 
The upward translocation of enormous quantities of 
soluble salts into the top foot or two of soil has ruined 
vast areas of the most productive lands of the arid regions. 

Salts in Natural Soils. — Where undisturbed by flooding 
and where the water-table is a considerable distance be- 
low the surface, soluble salts tend to accumulate at some 
distance beneath, rather than at the surface of arid soils. 
The rainfall is light and frequently so distributed that the 
moisture penetrates to a distance of only 3 to 4 feet 
in most soils. Much of the water that enters the soil 
is needed by the plants growing upon it and this water is 
extracted some distance below the surface. A large part 
of the movement of salts is in connection with capillary 
action, and because the capillary movement of moisture 
to the surface of the soil is reduced by the rapid drying 
out of the surface soil, little of the water is allowed to 
evaporate at the surface and deposit its soluble salts. 
Since there is little movement of water except through 

141 



142 MOVEMENT OF SOLUBLE SALTS 

roots ill deep arid soils, and since the first flush of water 
passing through a soil usually carries considerably more 
salts than the subsequent water, the usual movement of 
alkali under natural conditions is toward the lower point 
of rain penetration. In sandy soils or in regions where 
the rainfall is greater, the penetration of the water is 
greater than on the more impervious soils or where the 
rainfall is light, and the accumulation of the salts at dif- 
ferent depths varies accordingly. It was found in Cali- 
fornia (i6) that on a sandy loam soil with a rainfall of 8 
inches the greatest accumulation of salts was at a depth of 
3 to 4 feet, whereas in a coarse sandy soil in the same place 
the depth of greatest salts was below 4 feet. Where the 
rainfall was only 3 inches the maximum salt was at about 
18 inches in a sandy loam soil, whereas with 15 inches the 
bulk of the salts was at 5 feet. 

Salt Movement with Water. — When these arid lands 
are brought under irrigation, however, this balanced con- 
dition is frequently upset. The soil is kept so much 
more moist that capillary action is much easier, and not 
infrequently seepage and over-irrigation raise the water- 
table so high that upward movement is possible from the 
free water in the soil. Under such conditions, the alkali 
accumulations of the lower depths are moved to the upper 
zone of soil where they become of greatest injury to plants. 
It is in this manner that many of the formerly productive 
irrigated lands have been rendered useless. 

Diffusion of the salts in the soil plays a local part in the 
movement of alkali, but, according to the laboratory 
work of McCool and Millar (23) and others, diffusion 
causes changes for only a few inches about concentrated 
salt solutions, and the field observations of Mackie (24), 
Headden (14), Hansen (7), and others show that because 



SALT MOVEMENT WITH WATER 



143 



of the dilTcrences in the character and concentration of 
alkali in short distances vertically or horizontally, there 
must be movement of water before significant mo\'ements 
of salts are possible. 

The extent to which salts mo\-e with water passing 
through a soil has been studied by a number of investi- 




•-«S' 




r 




Fig. 17. — Cultivated Land that had to be Abandoned 

BECAUSE OF THE RiSE OF AlKALI. 



gators. In laboratory experiments, with alkali soils kept 
so continually moist that there was constant water move- 
ment, the author (9) has shown that alkali, principally 
sodium chloride, is very readily transported from one por- 
tion of the soil to another, either upward or horizontally. 
The salts became very concentrated in the upper inch or 
two of soil where the water was allowed to evaporate. 
The first water percolating through alkali soil contained 
several times as much salts as was found later. Tulay- 
kov (30) found salts moved gradually and more or less 



144 MOVEMENT OF SOLUBLE SALTS 

completely to the surface of a column of soil 150 cm. in 
height supplied with water at the bottom. Hilgard as 
well as Puchner (28) and others have noted a migration 
of salts upward and dowaiward as the moisture changed 
places. 

The latter experimenter, using quartz sand, loam, 
and rich humus soils, found the movement to depend 
somewhat on the chemical and physical properties of the 
soils. Powdery soils allowed the salts to move more 
readily than crumbly soils. Kossovich (20) reports a 
greater movement on a loess clayey soil than on a sandy 
soil and that sodium chloride hastened the rise of water 
while sodium carbonate impeded it. It is probable that 
the differences both in nature of the salts and their con- 
centration so often noticed in fields containing alkali are, 
in part at least, due to changes in the nature of the soils 
which in turn modify the rate of capillary action. In 
studies of the movement of moisture, Briggs and Lapham (2) 
conclude that "concentrated or saturated, solutions of all 
salts materially diminish capillary action," but that in 
dilute solutions the neutral salts had very little influence 
on capillary action. They found sodium carbonate to have 
a greater influence on capillarity than the neutral salts. 

The extent of the fluctuation of salts upward and down- 
ward under irrigation in the field has not been determined 
with any degree of accuracy. Hilgard considered the 
movement to be mostly in the top four feet. Considering 
the ease with which the salts move with the water and 
from observations of the movement of soluble salts with 
irrigation water when no alkali was present (11), it is very 
probable that the salts are frequently moved to great 
depths where not prevented by impervious soils or by a 
water-table. Investigations show that water is seldom 



EFFECT OF WATER-TABLE 145 

drawn to the surface by capillary action from a depth 
greater than 2 or 3 feet, so that the greater part of the alkali 
which penetrates beyond this depth never again reappears 
at the surface unless the water-table rises to within a few 
feet of the surface. Water movement below the top 2 or 
3 feet is probably caused by moisture removed by the plants 
or by the action of gravity so that it is improbable that 
there is such movement of salts other than local diffusion 
and movement with the gravitational, or free, water. 

Effect of Water-table. — Where the drainage is poor 
so that there is a rise of the water-table the conditions are 
modified accordingly. With a water-table near the sur- 
face, the soluble salts dissolved from the soil by down- 
ward movement are held where they may be drawn by 
capillarity to the surface and again accumulate. Head- 
den (14) observed that the, water in shallow wells rose in 
salt content from 2871 parts per million before an irriga- 
tion to 4444 parts per million twelve days following and 
then gradually fell to 2590 parts per million just before the 
next irrigation. 

He and also IMackie (24) noticed that the concentra- 
tion of the top of the water-table was greater than the 
lower depths and that there was a rather gradual de- 
cline in the soluble salts in the water with depth. As 
the water-table rises the most concentrated solutions are 
presented for upward translocation. Headden (14) made 
a rather detailed study of the effect of seasonal movement 
of water-tables from which he concluded that as the water 
fell much of the salts in the free water was retained by the 
soil so that the free water gradually became weaker as it 
sank and again increased as it rose. He (15) found that 
the kind and quantity of salts in the soil solution differed 
markedly from those found in the free ground water or 



146 MOVEMENT OF SOLUBLE SALTS 

from the alkali incrustations on top of alkali soil. Certain 
of the soluble salts were absorbed by the soil, while others 
moved somewhat more freely. Calcium sulphate was the 
most abundant salt in the soil solution with magnesium 
sulphate second, while sodium sulphate formed consider- 
able of the efflorescent matter on the surface, and the 
salts next the surface. Sodium chloride did not separate 
as readily as some of the other salts. Very little calcium 
sulphate left the soil to form part of the incrustation. 

Movement of Various Salts. — It has been noticed by 
numerous observers that the different salts move some- 
what independent of each other so that in comparatively 
short distances either vertically or horizontally rather 
marked differences are found. Experimenters have come 
to varying conclusions as to the ease of movement of the 
different alkali salts. Practically all field investigations 
have shown that the chlorides are the most sensitive to 
water movement. Both under arid alkali soils and where 
irrigation has shifted the salts to other positions, sodium 
chloride is generally found in its highest concentration at 
the point where the total salts are highest. Headden (12, 
13) states that while retention of salts differs with the soil, 
sodium sulphate was most markedly retained, sodium 
chloride slightly, and sodium carbonate hardly at all, 
and that "there is a tendency for the 'white alkali' to 
pass into the deeper seated waters" and out of the region 
where there is good drainage. King (18) reports sodium 
sulphate as being readily absorbed by the soil, while 
sodium chloride was not retained. The soil has a slight 
retentive power for the acid radical of sulphates but none 
for nitrates, chlorides, nor carbonates according to Waring- 
ton (32). Dimo (4) noticed accumulations of sodium 
chloride and sodium sulphate at a depth of 50 cm. in a 



MOVEMENT OF VARIOUS SALTS 147 

field soil, while in the deeper la}eis sodium bicarbonate 
and sodium carbonate gradually replaced the former salts. 
The work of Mackie (24) in California indicated that 
sodium carbonate was readily absoibed by the soils and 
therefore held its position in the soil well. On irrigated 
soils he usually found sodium carbonate in the greatest 
quantities near the surface, but on virgin soil its location 
varied in depth down to the hardpan. From results on 

f 





-_ - . - . .-.Hi 

Fig. 18. — Alkali Eating away the Fence Posts. 

land irrigated 4 or 5 years presented by Hilgard and 
Loughridge (16) it appears that sodium chloride moved 
upward to the first foot relatively faster than sodium sul- 
phate and considerably faster than sodium carbonate. 

Few data are at hand to show to what extent this dif- 
ference in the rate of movement of the different salts pro- 
ceeds under field conditions. Analyses of drainage water 
from alkali land near Salt Lake City, Utah, reported by 
Dorsey (6) show that in the course of three years the 
chloride was removed relatively faster than the other 
alkali salts when it constituted by far the greater part of 



148 MOVEMENT OF SOLUBLE SALTS 

the alkali. Drainage of a soil in California (22) removed 
about 85 per cent of the sodium chloride, 83 per cent of 
the sodium sulphate; drainage and conversion to sulphate 
reduced the sodium carbonate content to 65 per cent of 
the original quantity. 

Rate of Alkali Movement. — Theoretically, the alkali 
salts are so soluble that their removal from the soil by 
drainage should take only a short time, but in practice it 
often takes several years to reduce the salt content of 
seriously affected alkali lands sufhciently to produce 
crops. Dorsey (5) attempts to explain the difficult move- 
ment by the theory that the salts from the descending 
free-water solution are drawn into the capillary spaces 
of the soil where rapid downward movement is prevented. 
Subsequent downw^ard percolation is attributed to dif- 
fusion of the salts outward into the free-water spaces. 

Warington (32) states that the first water percolating 
through land containing soluble salts at the surface was 
much more concentrated than subsequent leachings but 
that where the chloride was first incorporated in the soil 
and then leached its concentration in successive leachings 
gradually increased. He explains this by assuming that 
the first water that comes from a drain passes through 
cracks and burrows of insects and comes direct from the 
surface, while that passing through the soil spaces alone 
does not arrive until later. 

To explain the extremely slow movement of soil solu- 
tions through alkali soils, especially those under laboratory 
or other conditions where the alkali is added to the soil as 
a single salt, Sharp (29) offers the theory that the alkali 
salts react with the colloids of the soil causing diffusion. 
He found that where solutions of sodium chloride or- sodium 
sulphate were in constant contact with the soil the rate of 



RATE OF ALKALI MOVEMENT 149 

percolation was increased, but that where soils treated 
with these salts were leached the rate of percolation was 
diminished. In one exj^eriment it was noticed that the 
quantity of suspended matter leached from soil containing 
sodium chloride was ten times that from the check and that 
the rate of percolation had been diminished to about one- 
tenth that of the check. It was further learned that once 
the sodium chloride was leached from the soil a larger 
quantity was required again to flocculate the soil and that 
it was more difficult thereafter to repair the deflocculated 
condition. A large number of investigators have noted 
an increase of calcium and magnesium and a decrease in 
sodium in alkali water after it had percolated through a 
soil. This exchange of bases is said by Sharp to result 
from displacement of calcium and magnesium by the 
sodium in the colloidal substances of the soil and the re- 
sulting increased diffusibility to be the cause of the retarded 
movement of the water. The removal of the calcium and 
magnesium from the soil is thought by him to be of less 
importance than the increased diffusibility of the colloids, 
although these bases are recognized as being important 
in the deflocculation of the colloids and in maintaining 
the proper physical properties of the soil. Contrary to 
Sharp's results, Pagnoul (26) did not find the sodium of 
sodium sulphate, nor to an appreciable extent sodium 
carbonate, to replace lime of the soil, and other experi- 
menters do not report sodium sulphate as replacing lime 
except v/here sodium chloride was also present. Pagnoul 
agrees with Sharp that lime replaces the bases of chlorides 
of potash, soda, and ammonia. If the degree of per- 
meability to water can be taken as a measure of the de- 
flocculation of soils, experiments by Beeson (i) show 
sodium chloride to be more than twice as powerful as 



150 MOVEMENT OF SOLUBLE SALTS 

sodium carbonate as a deflocculating agent but less than 
one-half as powerful as sodium nitrate. Percolation was 
at the rate of 1.2 cc. per hour for soil containing 1886 parts 
per million of sodium chloride and at the rate of 4.1 cc. 
per hour for soil containing 11,457 parts per million of 
sodium sulphate, while that of the untreated soil was at 
the rate of 10.2 cc. per hour. Hare (8), however, found 
sodium chloride much easier to leach into the deeper 
layers of the soil than sodium sulphate and that the dif- 
ference was many times greater in an adobe soil than in 
a sandy loam. It was with great difficulty that the sodium 
sulphate was leached downward in the adobe soil, the 
depth being 2 inches for three six-inch irrigations, while 
this amount of irrigation washed the sodium chloride to 
a depth of 32 inches, and four three-inch irrigations washed 
the sodium carbonate to a depth of 20 inches. The sodium 
chloride moved more freely than the other two salts in 
both adobe and sandy loam. 

The above experiments were performed with pure salts. 
Cameron and Patten (3) found that when using black 
alkali soils brought from the fields and containing notable 
quantities of sodium sulphate, besides the sodium car- 
bonate and small quantities of chlorides, the " neutral 
salts such as the chlorides in the presence of carbonates 
can be comparatively readily and completely leached 
from the soil. With continued leaching of soils contain- 
ing 'black alkali' there is an increase in the rate at which 
percolation takes place, due probably to the reduction of 
the amount of alkali present and its effect on the physical 
structure of the soil. Soils containing 'black alkali' 
can be reclaimed by leaching, but the time and the amount 
of water required are probably much greater than in the 
case of white alkali." 



REFERENCES 151 

Very little attention has been given to the effect of the 
different alkalies on the physical conditions of field soils; 
consequently, it is not known whether or not the rate of 
movement of salts under field conditions is checked by 
washing the salts out of the soil as in the above laboratory 
experiments. The last-mentioned experiment apparently 
indicates that when the salts are mixed, as under field 
conditions, the deleterious action of the neutral salts is 
not so great as under the laboratory mixing conditions. 

REFERENCES 

1. Beeson, J. L. The Physical Effects of Various Salts and Fertilizer 

Ingredients upon a Soil as Modifying the Factors which Control 
its Supply of Moisture. Jour. Am. Chem. Soc. 19 (1897), pp. 624- 
649. 

2. Briggs, L. J., and Lapiiam, M. W. Capillary Studies and Filtration 

of Clay from Soil Solutions. U. S. D. \. Bur. Soils, Bui. 19 (1902), 
40 pp. 

3. Cameron, F. K., and Fatten^ H. E. The Removal of Black Alkali 

by Leaching. Jour. .\m. Chem. Soc. 28 (1906), pp. 1639-1644. 

4. DiMO, N. A. Influence of Irrigation and of Increased Natural Hu- 

midity on the Process of Soil Formation and of the Transportation 
of Salts in the Soils and Subsoils of the Golodnoi (Hungary) Steppe. 
Russ. Jour. Exp. Landw. 15 (1914), pp. 136-138. (Abs. E. S. R. 34, 
p. 16.) 

5. DoRSEY, C. W. Accumulation of Alkali in Soil. U. S. D. A. Bur. 

Soils, Bui. 35 (1906), pp. 13-18. 

6. DoRSEY, C. W. Reclamation of Alkali Land in Salt Lake Valley, 

Utah. U. S. D. A. Bur. Soils, Bui. 43 (1907), 28 pp. 

7. Hansen, D. Experiments in the Production of Crops on Alkali 

Land on the Huntley Reclamation Project, Montana. U. S. D. A. 
Misc. Bui. 135 (1914), 19 pp. 

8. Hare, R. F., et al. Preliminary Tank Experiments on the Movement 

Changes in Composition and Toxic Effect on Wheat of Certain 
Salts in Sandy Loam and .A-dobe Soils. N. Mex. Sta. Bui. 88 (1913), 
32 pp. 

9. Harris, F. S. The Movement of Soluble Salts with the Soil Moisture. 

Utah Sta. Bui. 139 (1915), pp. 1 19-124. 
10. Harris, F. S., and Robinson, J. S. Factors Affecting the Evaporation 
of Moisture from the Soil. Jour. Agr. Res. 7 (1916), pp. 439-461. 



152 MOVEMENT OF SOLUBLE SALTS 

11. Harris, F. S., and Butt, N. I. Effect of Irrigation Water and Manure 

on the Nitrates and Total Soluble Salts of the Soil. Jour. Agr. 
Res. 8 (1917), pp. 333-359- 

12. Headden, W. p. AlkaU in Colorado. Colo. Sta. Bui. 239 (1918), 

48 pp. 

13. Headden, W. P. Colorado Irrigation Waters and Their Changes. 

Colo. Sta. Bui. 82 (1903), 77 pp. 

14. Headden, W. P. The Ground Water. Colo. Sta. Bui. 72 (1902), 

47 PP- 

15. Headden, W. P. A Soil Study, III. The Soil. Colo. Sta. Bui. 65 

(1901), 53 pp. 

16. H1LG.A.RD, E. W., and Loughridge, R. H. Distribution of Salts in 

Alkali Soils. Cal. Sta. Rpt. 1894-95, pp. 37-69. 

17. HissiNK, D. J. The Influence of Various Salt Solutions on the Per- 

meability of Soils. Jour. Chem. Soc. (London), 92 (1907), No. 542, 
p. 984. (Abs. E. S. R. 20, p. 16.) 

18. King, F. H. Investigations in Soil Management, 168 pp. (Madison, 

Wisconsin, 1904.) 

19. KoLOTOV, G. I. Movement of Salts in Seniiarid Soils. Abs. in Zur. 

Opyter. Agron. (Russ. Jour. Exp. Landw.), 12 (1911), pp. 832-833. 
(Abs. E. S. R. 38, p. 421.) 

20. KossoviCH, P. S. The Water-raising Capacity of Soils. Russ. Jour. 

Exp. Landw. 11 (1910), p. 734. (Abs. E. S. R. 38, p. 421.) 

21. Kravkov, S. On the Movement of Water and Salt Solutions in Soils. 

Jour. Landw. 48 (1900), pp. 209-222. (Abs. E. S. R. 12, p. 620.) 

22. Loughridge, R. H., and Shinn, C. H. Reclamation Tests with 

Gypsum in Alkali Soils. Cal. Sta. Rpt. 1891-92, pp. 80-90. 

23. McCooL, M. M., and Millar, C. E. Soluble Salt Content of Soils 

and Some Factors Affecting It. Mich. Sta. Tech. Bui. 43 (1918), 

PP- S-47- 

24. Mackie, W. W. Reclamation of White-ash Lands Affected with 

Alkali at Fresno, California. U. S. D. A. Bur. Soils, Bui. 42 (1907), 
pp. 16-17. 

25. Muntz, a., and Gandechon, H. The Diffusion of Fertilizer Salts in 

the Soil. Ann. Inst. Nat. Agron. 2 ser. 7 (1908), pp. 205-238. 
(Abs. E. S. R. 21, p. 23.) 

26. Pagnoul, a. Moisture and Absorptive Power of Soils. Terres 

Arables du Pas-de-Calais, Arras: 1894, 128 pp. (Abs. E. S. R. 6, 
p. 118.) 

27. Patton, H. E., and Waggaman, W. H. Absorption by Soils. U. S. 

D. A. Bur. Soils, Bui. 52 (1908), 95 pp. 

28. PdcHNER, H. Concerning the Transport of Soluble Salts by the 

Movement of Water in the Soil. Forsch. Geb. Agr. Phys. 18 (1895), 
pp. 1-26. (Abs. E. S. R. 7, p. 373.) 



REFERENCES 153 

29. Sharp, L. T. Fundamental Interrelationships l)ct\vecn Certain Soluble 
Salts ami Soil Colloids. Univ. Cal. Tub. A^r. Sd. i (igi6),|)i). 291- 



33^)- 



30. TuLAYKOV, N. Some Laboratory Kxpcrimenls on the Capillarity of 

Soils. Russ. Jour. E.\p. Landw. 8 (1907), pp. 629-O66. (Abs. E. 
S. R. 20, p. 517-) 

31. Tri.AYKov, N., and Kossovich, P. The Soils of the Muganj Steppe 

and Their Transformation into Alkali Lands by Irrigation. Ann. 
Inst. Agron. (Moscow), 12 (1906), pp. 27-255. (Abs. K. S. R. 21, 
p. 818.) 

32. Wartngton, R. Physical Properties of Soil, pp. 1S8-231. (Oxford, 

1900.) 



CHAPTER XII 
METHODS OF RECLAIMING ALKALI LANDS 

No single method of reclamation is adapted to all alkali 
lands. Many conditions must be considered in deciding 
what methods to adopt. The source of the alkali, the 
texture of the soil, the slope of the land, the depth of the 
water-table, the price and supply of reclaiming materials, 
the kind of crops that will grow in the climate, the value 
of the reclaimed land, and a number of other factors must 
be taken into account before deciding the advisability of 
reclaiming a given alkali soil and the methods to be used 
in case reclamation appears economical. Whatever the 
method, the goal is the same; each aims to check any in- 
creased accumulation of salt and to reduce the present 
harmful quantities of alkali to a point at which the growth 
of crops will not be hindered. 

The Source of Contamination. — The first step in the 
reclamation of alkali land is to discover the source of the 
salt. Intelligent systems of improvement first discover 
and remove the cause of the accumulation. As with 
human disease, an ounce of preventative is worth a pound 
of cure. Most of the effort spent in securing temporary 
relief is wasted if the trouble soon returns. Work is done 
to much better advantage if done with the idea of securing 
permanent results. 

As pointed out in Chapter X, alkali comes to the soil 
in a number of very distinct ways. These must be recog- 
nized in deciding which method of reclamation is best 

154 



REDUCING EVAPORATION 155 

adapted to the conditions. Where an irrigation canal 
passes through a formation that is high in soluble salts 
the water becomes alkahne and carries the soluble material 
to the land where the water is applied. A canal in a forma- 
tion of this kind becomes porous when the salts are dis- 
solved. This allows seepage water to percolate more 
readily from the canal, increasing the quantity of water 
which comes out on land below; this in turn causes water- 
logging together with deposition of alkali salts. Lining 
the canal with cement over the salt-bearing formation 
will do more toward permanent reclamation than any 
number of temporary devices on the land itself which do 
not remove the source of the trouble. 

Often a large area becomes water-logged from a single 
source, and in arid soils water-logging is generally fol- 
lowed by alkali accumulation. A ditch across the head 
of the land to cut off the water in cases of this kind will 
often prevent or overcome the difficulty without applying 
methods of reclamation on the land itself. 

Some soils contain a layer several feet below the surface 
in which the salt is very concentrated. Where this is the 
case, every effort should be made to prevent a rise of the 
salt to the surface where it will hinder crop growth. If 
it remains at considerable depth, it may be entirely harm- 
less, whereas it might entirely prevent plant growth if it 
rose to the root zone. These examples show the relation 
of reclamation methods to the source of alkali. 

Reducing Evaporation. — The chief method by which 
alkali accumulates at the surface of the soil is through 
evaporation. The author (4) has shown the ease with 
which salts move with moisture through the soil. W^hen- 
ever water evaporates from the soil surface more water is 
moved to the surface by capillarity and the process re- 



156 



RECLAIMING ALKALI LANDS 



peated. Thus, there may be a constant stream from the 
subsoil to the surface, particularly if the water-table is 




Fig. 19. — Typical Hard Pan Found in Arid Soils. 

within two or three feet of the surface. All the water 
that moves transports some salt, and since none of the 
salt can be evaporated, all of it remains as a surface ac- 



REDUCING EVAPORATION 157 

cumulation. If the soil is \cry low in soluble salts no 
harm may be done, but arid soils usually contain suflicient 
salt to render high exaporation dangerous. 

If virgin soil contained 3000 parts per million of alkali, 
the growth of most crops would not be greatly liindered; 
but if through a constant movement of salt to the surface 
the salt of the top four feet were concentrated in the upper 
six inches, it would contain 24,000 parts per million, which 
would make it entirely unsuited to crop production with- 
out reclamation. If evaporation is reduced to a mini- 
mum, an accumulation of this kind is checked. In the 
reclamation of alkali land by any method, it is desirable 
to prevent evaporation as nearly as possible, because 
evaporation causes the salt to accumulate where it will 
do most harm. 

In practice, many devices to reduce evaporation are 
employed. These usually consist of cultivating the soil, 
shading it, or the estabhshing of a good mulch by adding 
manure, straw, leaves, or sand. Of the various materials 
to be added, manure is usually to be recommended since 
it has sufficient beneficial effect in addition to the mulch- 
ing to pay for its use, while others are of questionable 
economic importance. 

The most practical means of preventing evaporation is 
through cultivation. An unstirred soil, particularly if it 
is heaxy — as many alkali soils are — forms a crust 
which acts as an excellent conductor of moisture. Break- 
ing up this crust by cultivation leaves the soil loose and 
with but few points of connection with the lower layers 
of soil. As a result evaporation is slight even though the 
subsoil remains moist. It is particularly important that 
the land be cultivated soon after irrigation since evapora- 
tion at that time is especially high. 



158 RECLAIMING ALKALI LANDS 

Harris and Robinson (5) have shown that shade is very 
effective in reducing evaporation. This suggests the 
desirabiHty of keeping alkali land constantly shaded, 
preferably by a crop, which not only shades the soil but 
also causes the water to pass into the air through the 
plants without coming to the surface. A growing crop 
may therefore be considered as one of the most important 
agencies in the reclamation of land containing small 
quantities of alkali. 

A water-table near the surface is the chief cause of 
harmful evaporation. It is difficult to prevent the pas- 
sage of large quantities of water to the surface when there 
is an unlimited supply 2 or 3 feet below. The prevention 
of alkali accumulation calls for a lowering of the water- 
table to several feet from the surface. The growing of 
green manure crops instead of leaving the land uncropped 
is one way of reducing the surface accumulation of 
alkali. 

Plowing Under of Surface Alkali. — Hilgard (9) has 
shown at the Tulare Substation, California, that the injury 
caused by alkali was reduced by plowing the surface ac- 
cumulation under. Part of a very bad alkali spot was 
trenched to a depth of two feet and the surface soil thrown 
to the bottom. The spot thus treated produced good 
wheat crops for two years, which was the time required 
for the alkali to return to the surface. Ordinary plowing 
is to some extent similar to the above treatment; hence 
the tendency of salts to accumulate at the surface by 
evaporation of water is in part overcome by ordinary 
field practices. 

In order that this operation may be effective, the plow- 
ing should be as deep as possible, since salt turned under 
only 3 or 4 inches deep would return rapidly to the sur- 



REMOVING FROM SURFACE 159 

face, or even worse, the liighcst concentration would l)e 
in the soil layer where young plants were getting Uieir 
start. The plowing under of alkali cannot be considered 
in any sense as getting rid of it. The most that can be 
claimed is that injury is retarded till drainage or some other 
permanent means of elimination begins to operate. 

Removing from Surface. — In certain cases where most 
of the salts have accumulated at the surface, it is possible 
to remove large quantities without the use of covered 
drains. Surface removal is accomplished by scraping or 
sweeping off the salt or by dissolving it and then draining 
off the solution. Scraping and sweeping, in order to be 
practical, would call for a higher concentration of salt 
than can be removed by dissolving. 

Where the salt is to be removed in solution, as may be 
done in exceptional cases, the land may be diked in such 
a way that water can be made to stand several inches deep 
over the surface for a number of hours till most of the salt 
is dissolved. The solution is then drawn off carrying with 
it a large percentage of the alkali. Water may in this 
way be added and drawn off several times in order to make 
the treatment effective. It is not necessary to let the 
water stand more than a short time since the salt dis- 
colves quickly and if allowed to stand would reenter the 
soil with percolating water. This method is not to be 
recommended under many conditions. 

A method of reclamation somewhat similar to the above 
requires water to stand on the land for long periods. By 
this means the salt is gradually washed down into the soil 
out of the reach of plants. Where conditions are favor- 
able, however, it is much better to carry the salt entirely 
out of the land by drainage, since it will rise again if simply 
washed down. 



160 RECLAIMING ALKALI LANDS 

The reclamation of land by flooding is used extensively 
in the lower Nile Valley in Egypt. Details of the methods 
used are described by Means (12). After land has been 
reclaimed by flooding it is desirable to raise a crop that 
can endure alkah and water till the soil is in a proper 
condition for other crops. Rolet (12) recommends rice 
for climates in which it will grow. White sweet clover 
{Melilotus alba) is also an excellent crop for this purpose. 

Neutralizing Sodium Carbonate. — The methods used in 
removing most of the salts are not entirely satisfactory 
for sodium carbonate, or black alkali. This salt dissolves 
organic matter from the soil and deflocculates the particles, 
thereby injuring the soil structure and making the pene- 
tration of water very slow. The high direct toxicity of 
this salt also renders it much more harmful than the 
sulphates. Hilgard and his associates (8), working in 
CaHfornia, found that under suitable conditions sodium 
carbonate can be made to react with gypsum to form 
sodium sulphate and calcium carbonate. The reaction is 
as follows: 

NaaCOs + CaS04 = Na2S04 + CaCOg. 

This changes the alkali from a very injurious to a much 
less harmful salt. 

Shinn and Hilgard (15) used 3000 pounds of gypsum 
to the acre in Tulare, California, with good results. The 
best results were secured on plats treated with gypsum in 
connection with drainage. Later reports of the experi- 
ments made by Hilgard and Loughridge (8) and by 
Shinn (14) show that the treatment continued to be suc- 
cessful. In some cases gypsum was used at the rate of 
7.7 tons to the acre annually for thirteen years with a 
gradual amelioration of the alkali spots. In the four 



OTHER CHKMICAL TREATMENTS 161 

years following 1897 a six-acre vineyard received 34,000 
pounds of gypsum or about 4^ tons a year. This was 
applied at a cost of less than four dollars an acre each 
year which was a small cost in proportion to the returns. 

As a result of experiments in the San Luis Valley, (Colo- 
rado, Headden (7) suggests the use of nine pounds of 
gypsum for each pound of black alkah in the soil and the 
removal of the alkaU by surface irrigation. 

Extensive experiments by Breazeale (i) are reported as 
showing that the field application of gypsum probably 
has no effect in overcoming black alkali if the soil already 
contains soluble sulphates in appreciable quantities or if 
the irrigation water contains these salts. It seems, there- 
fore that while g}psum is useful under some conditions, 
it is not by any means a universal panacea for all black- 
alkali troubles. 

Other Chemical Treatments. — The use of chemical 
substances other than gypsum has frequently been tried 
in overcoming alkali. Symmonds (17) found in pot ex- 
periments that alkali soil that was treated with 0.2, 0.5, 
and I per cent of nitric acid produced more than 5 
times the yield of wheat that was produced by the un- 
treated soil. He (16) later carried on a similar experiment 
in the field where 600 pounds of nitric acid to the acre of 
land were mixed with artesian well water and sprinkled 
on the soil. The results showed a great increase in yield 
due to the treatment. 

Lipman (10) has obtained excellent results in treating 
alkali soil with small quantities of sulphuric acid. 

The use of stable manure on alkali land has long been 
known to improve it for crop production. It has indirect 
value in reducing evaporation as well as the more direct 
action on the soil and plants. 



162 RECLAIMING ALKALI LANDS 

Cropping with Alkali-resistant Crops. — Allowing land 
to remain uncropped promotes accumulation of alkali at 
the surface. It is desirable, therefore, to maintain some 
kind of plant growth on land that is being reclaimed even 
though the plant is not the most desirable. Any plant 
growth is better than none. In soils that are so highly- 
alkaline that no ordinary crops will grow, certain salt 
weeds will thrive. It is much better to have them grow- 
ing than for the land to be bare. When these weeds 
cover the land the temptation is to burn them, but such 
a practice leaves the alkali absorbed by the plant on the 
top of the land with the ash. Some alkali-resistant plants 
take up large quantities of salts, which might be perma- 
nently removed from the land if the weeds were harvested 
and hauled off rather than being burned where they grew. 

In Chapters VI and XIV there is a full discussion of 
the crops that do well on alkali land. From these lists, 
crops may be selected for use during the various stages 
of reclamation. 

Drainage. — The only permanent way to reclaim alkali 
land is to remove the excessive salt. This can best be 
accomplished by some system of drainage, the various 
t>pes of which are described in Chapter XIII. It may be 
said, therefore, that alkali reclamation and drainage are 
almost synonymous terms. Of course drainage is not 
equally effective under all conditions. Heavy, compact 
soils containing large quantities of black alkali respond 
slowly to drainage, whereas open soils which may contain 
large quantities of sulphates and chlorides may have 
these salts effectively washed out in a short time. 

A good example of the rate of removal of salts is had in 
the Swan Tract (3) near Salt Lake City. Work was begun 
in 1902 on this forty-acre farm by the U. S. Department 



DRAINAGE 



1 63 



of Agricullure Bureau of Soils and the Utah Agricultural 
Experiment Station cooperating. By the end of igo,^ 
5,051,770 cubic feet, or 51.8 per cent, of the water added to 
the tract came out through the drains. This water carried 

Table XVII. Alkali Salts Removed by Drainage During 
Three Years. Swan Tract Near Salt Lake City 



Month 



igo2 
September 
October . . 
November 
December 

1903 
January. . 
February. 
March .'. . 

April 

May 

June 

July 

August . . . 
September 
October . . 
November 
December 

1904 
January. . 
February . 
March .'. . 

April 

May 

June 

July 

August. . . 
September 



Total 



Water Added per .\cre 



Rain 

and 

Snow 

(.\cre inches) 



I. 18 
11=; 



14 



13.21 



Irrigation 
(.Acre inches) 



I .g(l 
6.47 



5 23 

4.66 

11.65 

14.62 

16. 20 

2.42 

3.88 

.28 



06 
2g 
76 
64 
4.26 
09 
1323 
52 

110.72 



Total 
(Acre inches) 



1 .96 
6.47 
I. 18 
11=; 



1.49 
2.06 
1.29 
1.76 
2.63 

4-55 
11.66 

13-35 
565 



123.69 



S.iVLTS 

.\ddf.d in 
Irrig.ation 

Water 

(Pounds per 

acre) 



696 . 1 

2,288.0 



1,858 
1,655 
4,i3'H 
.■5,192 
5,754 
85Q 
1,378 
99 



533 

732 

458 

625 

938 

1,513 

3,939 

4,692 

1,960 



Salt in 

Drainage 

Water 

(Pounds per 

acre) 



45,57; 



3,805 
4,878 
8,845 
4,695 



9,780 

5,370 

14,768 

663 

14,178 

8,630 
13,912 
30,544 
41,353 
2I,C25 

3,159 
1,099 



473 
11,891 

13,049 

9,558 

1,537 

787 

0,634 

17,776 

14,480 



265,889 



Net Salts 

Lost from 

Soil 

(Pounds 

per acre) 



2,583 
8,845 
4,695 



9,780 

5,370 

14,768 

663 

12,320 

6,975 

9,774 

25,352 

35,599 

20,166 

1,781 

1,000 



60 

11,159 

12,591 

8,933 

599 

- 726 

5,695 
13,084 
12,520 



223,586 



164 



RECLAIMING ALKALI LANDS 



out 3648 tons of salt over the measuring weir in addition 
to the salt washed to lower depths by percolating water. 
Tables XVII and XVIII show in detail the rate of re- 
moval of the salts. 



Table XVIII. Quantities of Alkali at Different Depths 

OF Soil on Certain Dates and Composition of Drainage 

Water. Swan Tract near Salt Lake City 





September, igo2 


May, 1903 


October, 1903 


October, 1904 


Soil 
Section 


Alkali 

in 

Soil 

(p.p.m.) 


Part of 

4 ft. 

Total 

(per cent) 


Alkali 
in 

Soil 
(p.p.m. 


Part of 

4 ft. 

Total 

(per cent) 


Alkali 
in 

Soil 
(p.p.m.) 


Part of 

4 ft. 

Total 

(per cent) 


Alkali 

in 

Soil 

(p.p.m.) 


Part of 

4 ft. 

Total 

(per cent) 


First Foot .... 
Second Foot. . 
Third Foot... 
Fourth Foot. . 


17,038 
19,250 
22,075 
24,775 


20 
23 
27 
30 


6,238 

8,125 

13,325 

15,813 


14 
19 
31 
63 


1,263 
2,288 
4,125 
7,608 


8 

15 

28 

49 


475 
1,600 
2,650 
6,250 


4 
13 

24 
57 


Total 


83,138 




43,501 




15,284 
3,821 




10,975 


-• 


Average — 


20,785 




10,875 






2,744 





Chemical Analysis of Drainage Water (in Paris per 1,000,000) 



Constituent 


Seepage Water 

from Tile 
Drain before 

Irrigating, 
Oct. 9, 1902 


Drainage 

Water, 

June 18, 1903 


Drainage 

Water, 

April 4, 1904 


Drainage 

Water, 

May 10, 190S 


Drainage 

Water, 

June 26, 1906 


Ca 

Mg 

Na 

K 

SO4 

CI 

HCO3 

CO3 


45 

96 

6,966 

319 

3,870 

7,650 

1,329 

71 


72 

257 

11,771 

260 

8,886 

12,070 

937 

55 


61 
162 

7,262 
269 

3,531 

8,881 

800 

40 


37 

70 

3,660 

1-08 

2,143 

3,958 

666 

59 


37 

89 

3,924 

126 

2,288 

4,312 

695 

60 


Total Solids . 


20,346 


34,308 


21,006 


10,701 


11,531 



DRAINAGE 165 

Hart (6) gives an example of a tract on which before 
drainage the ground water stood within 2 feet of the 
surface. A white crust of salts covered the surface and 
nothing of value grew on the land, the only vegetation 
being an occasional salt weed. The average salt content 
for tlie first 4 feet of depth was 2.25 per cent. A drain- 
age system was installed and in a month so much of the 
excess water in the soil was removed, that the water- 
table was practically down to the level of the drains. 
The drainage water was very high in salt. By the end of 
the month an analysis showed the salt content of the soil 
to have been reduced to i per cent. The ground surface 
was cultivated and irrigated with a limited supply of water 
and crops were planted. These gave only fair results. 
Meanwhile the higher temperature of summer had in- 
creased evaporation and the average salt content for 4 
feet was found to have increased to 1.28 per cent in spite 
of drainage. A near-by uncultivated and unirrigated spot 
which had been affected to some extent by the drainage 
system showed an average salt content for the first four 
feet of 1. 51 per cent. It was evident that drainage alone 
would never reclaim the tract; hence, a heavy flooding 
was given which reduced the average salt content for the 
first 4 feet to 0.43 per cent, less than one-fifth of the origi- 
nal content. At the same time the near-by uncultivated 
spot showed an average salt content for the first 4 feet of 
1.73 per cent, an increase which was caused by percolation 
from flooding the adjacent land. 

Thousands of examples could be given to show the 
effectiveness of drainage in reclaiming alkali lands. ISIany 
failures have also been recorded. These have resulted 
from improper methods which were decided on before all 
conditions were studied and also from the fact that the 
drainage system was expected to do everything. 



166 RECLAIMING ALKALI LANDS 



REFERENCES 

1. Breazeale, J. F. Formation of "Black Alkali" (Sodium Carbonate) 

in Calcareous Soils. Jour. Agr. Rsch. lo (191 7), pp. 541-590. 

2. Brown, C. F., and Hart, R. A. The Reclamation of Seeped and 

Alkali Lands, Utah Sta. Bui. iii (1910), pp. 75-92. 

3. DoRSEY, C. W. AlkaU Soils of the United States. U. S. D. A. Bur. 

of Soils, Bui. 35 (1906), 179 pp. 

4. Harris, F. S. The Movement of Soluble Salts with Soil Moisture, 

Utah Sta. Bui. 139 (1915), pp. 119-124. 

5. Harris, F. S., and Robinson, J. S. Factors Afifecting the Evapora- 

tion of Moisture from the Soil. Jour. Agr. Rsch. 7 (1916), pp. 439- 
461. 

6. Hart, R. A. The Drainage of Irrigated Farms. U. S. D. A. Farmers' 

Bui. 805 (1917), 31 pp. 

7. Headden, W. p. "Black Alkali" in the San Luis Valley. Colo. Sta. 

Bui. 231 (1917), pp. 3-15. 

8. HiLGARD, E. W., and Loughridge, R. H. The Distribution of the 

Salts in Alkali Soils. Cal. Sta. Rpt. 1895, pp. 37-69. 

9. HiLGARD, E. W. Soils, pp. 455-484. (New York, 1906.) 

ID. LiPMAN, C. B. New Experiments on Alkali Soil Treatment, Univ. 
Cal. Pub. Agr. Sci. i (1915), pp. 275-290. 

11. Means, T. H. Reclamation of Alkali Lands in Egypt. U. S. D. A. 

Bur. of Soils, Bui. 21 (1903), 48 pp. 

12. RoLET, A. Cultivation of Salt Lands. Jour. Agr. Prat. n. scr. 9 

(1905), No. 22, pp. 710-712. (Abs. E. S. R. 17, p. 814.) 

13. Sandsten, E. p. Reclaiming Niter Soil in the Grand Valley. Colo. 

Sta. Bui. 235 (1917), 8 pp. 

14. Shinn, C. H. Alkali Reclamation at Tulare Substation. Cal. Sta. 

Rpt. 1899-190X, Pt. n, pp. 204-213. 

15. Shinn, C. H., and Hilgard, E. W. Reclamation of Alkali Land with 

Gypsum at the Tulare Station. Cal. Sta. Rpt. 1893-94, pp. 145- 
149. 

16. Symmonds, R. S. Experiments with Nitric Acid in Alkaline Soils. 

Agr. Gaz. N. S. Wales, 21 (1910), No. 3, pp. 257-266. 

17. Symmonds, R. S. Note on Action of Nitric Acid in Neutralizing 

Alkaline Soil. Jour, and Proc. Roy. Soc. N. S. Wales, 41 (1907), 
pp. 46-48. 

18. TiNSLEY, J. D. Drainage and Flooding for the Removal of Alkali. 

N. Mex. Sta. Bui. 43 (1902), 29 pp. 

19. Weir, W. W. A Preliminary Report of the Kearney Vineyard Ex- 

perimental Drain. Cal. Sta. Bui. 273 (1916), pp. 103-123. 



CHAPTER XIII 
PRACTICAL DRAINAGE 

During the early years of irrigation in America no 
provision was made to remove the excess water that always 
collects in the lowlands of irrigated districts. This is one 
of the chief reasons for the accumulation of alkali. The 
modern up-to-date irrigation system should include some 
method of drainage whereby any excess of water is carried 
out of the land; for there are always a few farmers who, 
to the detriment of themselves and their neighbors, use 
too much water. A drainage system laid out at the same 
time as the irrigation system will in some cases be more 
simple than one installed after the land becomes a bog. 
In swampy places drain ditches are constructed with 
difl&culty and tile cannot be laid evenly and securely. 
Unfortunately, the reclamation of most alkali land is not 
undertaken until after the condition has become bad. 
This means that many difficulties are encountered. Of 
course it would not be wise to install drainage when the 
irrigation system is put in unless there is likelihood of 
water-logging. The problem is doubly complex since not 
only must the excess soil water be removed but the alkali 
must also be washed out. 

Advantages of Drainage. — Where drainage systems are 
installed on land there is generally a complete transforma- 
tion; many conditions favoring crop growth are improved. 
Most important in an alkali soil is the removal of the 
excessive salt. In many soils where the salt content is 

167 



168 



PRACTICAL DRAINAGE 



not high enough entirely to prevent crop growth, there is 
sufficient to reduce the yield to a point that is unprofit- 
able. The expenses are practically the same in raising 
half a crop as a full one. In the one case farming is carried 
on at a loss, and in the other a good profit may be realized. 
Thus, removing alkali by drainage may make highly pro- 
ductive miUions of acres of land that is only moderately 













Fig. 20. — Field Ready for Laying Tile. 



successful. There are also millions of acres at present 
wholly unproductive that may be made to yield bounte- 
ously by removing the alkali. 

Drainage removes the excessive water from the soil. 
By lowering the water-table the plant is given a larger root 
zone from which to draw both food and water. If only 
the surface foot or two can be drawn on for food the plant 
cannot be expected to be so well supplied with nourish- 
ment as it would with a feeding area of five or six feet. 



ADVANTAGES OF DRAINAGE 169 

Strange as it may seem, drainage increases the water 
supply of tlic i)lant and reduces the injury that is likely 
to be caused by drought. Roots do not readily penetrate 
into the ground water. They are confined to the zone 
above the water-table from wliich they absorb capillary 
water. Free water is unavailal)le to them. A water-table 
near the surface means, therefore, that the plant can absorb 
water from only a hmited area. In case of drought when 
the water-table is likely to be lowered rapidly the plant 
has but a shallow root system which is unable to endure 
drought so well as a root system which extends well into the 
soil and is able to take up moisture from a deep soil zone. 

Drainage allows the soil to become warm early in spring. 
The high specific heat of water makes it slow to become 
warm. This has great practical significance since a slow, 
cold soil delays spring work and retards the development 
of the young plant at a critical period in its life history. 

Roots require air for their normal functioning. If free 
circulation of air through the soil is retarded by water- 
logging, the plant does not get sufficient air for its best 
growth. This condition reflects itself in the yield. Covered 
drains promote the free movement of air through the soil; 
this may help to account for the wonderful results that 
follow drainage in cases where the water-table is not close 
to the surface and alkali is not injurious. 

Going hand in hand with better aeration is the better 
condition for the growth of desirable microorganisms. 
Decay of vegetation in absence of sufficient air takes place 
as putrefaction which results in products toxic to plant 
growth. Nitrification, nitrogen-fixation, and normal plant 
decay require air. If it is not present the organisms 
promoting these beneficial processes will be replaced by 
undesirable ones. 



170 PRACTICAL DRAINAGE 

Water-logged land has a tendency to heave in freezing. 
This results in the winter-killing of such crops as alfalfa, 
clover, and fall grains. Where the soil is not covered with 
a protective layer of snow, winter-killing may be one of 
the most serious handicaps to farming. Anything that 
reduces it will add greatly to the farmer's profits. 

The tilth, or structure, of the soil is benefited by drain- 
age. An undrained soil puddles readily, whereas one that 
is drained tends to form the crumb-like structure which 
is sought by the farmer. 

Determining the Need of Drainage. — As with all other 
expenses, that required for drainage should be investigated 
before it is incurred. It would of course be folly to spend 
15 or 20 dollars an acre draining land that would not be 
benefited thereby. Drainage is usually carried on to re- 
move either excess water or excess alkali. In spite of 
secondary benefits, it is doubtful if it would pay to drain 
in most cases unless one of these undesirable conditions 
existed. 

An excess of water can easily be determined by boring 
test holes with a soil auger. The surface indications are 
not an absolutely reliable guide. In many soils having a 
dry, baked crust at the surface, borings will reveal free 
water 2 or 3 feet below the surface. The color and thrift 
of the vegetation are valuable aids in determining the need 
of drainage, but the final test should be made by the 
use of an auger. 

Excessive quantities of alkali can readily be determined 
by a chemical analysis. Water extracts of the soil can 
easily be tested for chlorides, sulphates, carbonates, and 
nitrates. With information of this sort available it is 
possible to say whether or not some of the salts should be 
removed. The electrolytic bridge is very useful in this 



TYPES OF DRAINS 



171 



connection to determine the approximate concentration 
of total soluble salts. For exact work, chemical methods 
should be resorted to, but for general reconnoissance 
work the bridge can be used to advantage. 

Types of Drains. — After deciding that the land needs 
drainage, the next point to settle is the type of system to 



f«f»w 




Fig. 21. 



Boggy Alkali Land that is Difficult to Drain 
WITH Short Tile. 



install. No one system is best for all conditions. On 
some projects a combination of systems can be used to 
advantage. 

The open drain on account of its low initial cost has 
been used rather extensively. It has some advantages 
and many disadvantages. Among its advantages is the 
fact that its action is at all times under the observation 
of the farmer. Any obstruction can easily be found and 
removed. The fact that the farmer can do most of the 



172 



PRACTICAL DRAINAGE 



work himself at odd times and does not have to pay for 
materials makes it possible at times to put in an open 
ditch, whereas a closed drain would be beyond his reach. 
Among the disadvantages of the open drain are the facts 
that the original cost does not represent the total outlay. 
Every year, and often several times during the year, 
open drains must be cleaned. The banks cave off or 
other obstructions fall in and interfere with the effective- 




FiG. 22. — Open Ditch Used to Carry Away the Drainage Water 
FROM A Large Area. Covered Drains Empty into this Ditch. 

ness of the drain. Weeds growing on the banks and in 
the bottom of the ditch are a constant source of annoy- 
ance. Considerable la^nd that could be cultivated if the 
drain were covered is made useless by the open ditch, 
which also cuts the land up into smaller fields causing 
inconvenience in plowing and performing the other farm- 
ing operations. Open ditches are always a source of danger 
for farm animals that may fall in them and be injured. 
These many disadvantages usually turn the preference 
toward some form of covered drain, except in such cases 



TYPES OF DRAINS 



173 



as require a main drain to carry off large quantities of 
water. Several closed drains. may open into a main open 
ditch. 

Many types of closed drains are in operation. The 
main requirement is to preserve through the subsoil an 
open channel that will carry off percolating waters. A 




Fig. 23. — Machine for Making Drains in Heavy Soil without 
THE Use of Tile. 

ditch is dug and some material that will maintain the 
channel open placed in it. Rocks, brush, straw, timber, 
and tile are all used. 

In certain heavy gumbo soils a special device known as 
a gopher machine, shown in Fig. 23, makes a hole through 
the soil that does not require filling. In this device a tor- 
pedo about 8 inches in diameter is attached to a subsoiling 
point, which is held in the ground by a heavy wheeled 
frame. The depth at which the torpedo is pulled through 



174 PRACTICAL DRAINAGE 

the soil can be regulated by the operator. In making 
drains this machine begins at the outlet end and moves 
toward the higher land leaving a gopher-like hole through 
which the drainage water passes. Such drains can be made 
25 feet apart for about $5 an acre. These will last 5 or 6 
years in the right kind of soil. If any of them happen to 
become clogged, new ones may be made between the others. 

The type of covered drain to use depends on a number 
of factors.. In wet brush land where rock and lumber are 
scarce and where tile cannot be had, rush and straw may 
be used to good advantage, although usually less ef- 
ficiently than some of the more permanent types. 

Brown and Hart (3) found lumber drains to be very 
effective in a swamped soil that would not remain firm 
enough to hold tile. Rock properly placed in the trench 
has long been used to keep open the water channel. 

These various unusual types of drains are unimportant 
in comparison with tile. The most common kinds are 
clay tile, either porous or vitrified. Many types of clay 
tile are to be had. These are so well and favorably known 
that further discussion seems unnecessary here. Cement 
tile is being used to some extent, but its use on alkali land 
is attended with some risk which is explained below. 

Cement Tile for Alkali Land. — The ease with which 
cement tile can be made in some localities has encouraged 
its use for drainage. This has often resulted in failure, 
because it has been found that under certain conditions 
the cement is attacked and destroyed by some of the al- 
kali salts. This observation has led to considerable study 
on the relation of soluble salts to cements and their de- 
terioration. 

Burke and Pinckney (4) found that to cause weakening 
it was necessary for salt solutions to penetrate the concrete. 



CEMENT TILE FOR ALKALI LAND 



175 



Weakening results from the formation of compounds that 
expand and break up the concrete. Later the soluble 
compounds leach out leaving the material not nearly so 




Fig. 24. — Poorly Made Cement that is being 
Crumbled by Alkali. 



Strong. Neat cement that excluded absorption was not 
injured by alkali solutions. Meade (q) found that even 
very dilute solutions of the salts of magnesium and the 
sulphates in general have a destructive action on concrete. 
Cements low in alumina were less affected than others. 



176 PRACTICAL DRAINAGE 

Work done at the U. S. Bureau of Standards (i, 14) 
shows how Portland cement concrete mortar, if porous, 
can be disintegrated by the mechanical force exerted by 
the crystallization of salts in its pore spaces. Mixtures 
leaner than one part cement to three parts of aggregate 
were found to be unsuitable for use in localities having a 
soil high in alkali. 

Headden (6) found that in the presence of solutions oT 
sodium sulphate and sodium carbonate a chemical de- 
composition of the cement takes place with a removal 
of silicic acid and lime which destroys the cohesiveness of 
the concrete. 

Steik (12) found that, of the great number of solutions 
tested, the 5 per cent sodium sulphate had the greatest 
disintegrating action. Solutions containing chlorides, sul- 
phates, and carbonates all had some effect. Mortars were 
found to disintegrate faster than neat cement, which is 
similar to the findings of Sims and Dieckman (n). The 
latter author found that density and age are very important 
factors in helping cement to resist alkali. Steik believes 
that the ultimate cause of the disintegration of cement 
by alkalies is due to the formation of compounds in the 
cement, which subsequently are removed by solution. 

These experiments all show the necessity for care in 
the use of cement tile to drain alkali land, but if the cement 
is properly made it is fairly satisfactory. 

Preliminary Survey. — Before actual trenching is be- 
gun it is important to make a preliminary survey to de- 
termine the nature of the subsoil and the slope of the land 
to be drained. A great many test holes made with an 
auger will reveal the location of pervious and impervious 
strata. This information is necessary in deciding the 
depth, location, and direction of the drains. A system 



LAYING OUT 'VllK SYSTEM 



177 



installed without taking account of these conditions is 
likely to be inefficient and expensive. 

Laying out the System. — After the preliminary survey 
is made the system can be laid out and the location and 
depth of each drain determined. The district should be 




yi 



Fig. 25. 



Method of Establishinc. Grade of 
Drains 



mapped in such a way that the data obtained in the pre- 
liminary survey will show the contour of the surface, the 
texture of the soil and subsoil, and the ground- water 
condition. On this map the drainage system may be 
drawn in such a way that intersecting joints, the sizes of 
tile, and other data can be preserved for future use. These 
data are extremely valuable in locating trouble. The 
memory is not sufficiently accurate to be relied on for this 



178 PRACTICAL DRAINAGE 

information, and it is a good idea to preserve the record 
for the use of some one besides the original drainer of the 
land. 

In laying out the system the depth of the drains, the 
size of tile, the slope of the drain, and the distance apart 
must be given careful consideration and will vary with 
each set of conditions. These factors depend somewhat 
upon each other. For example, the steeper the grade 
the smaller the tile may be, and the deeper the drain the 
farther apart they may be placed. In general, tile should 
be placed from 5 to 7 feet deep and the space between 
tile lines will usually vary from 200 to 1000 feet. 

Size of Drains. • — A number of formulas have been 
worked out to help in deciding the size of tiles that will be 
efficient and economical. Poncelet's formula for de- 
termining the velocity of flow in drains, which has found 
considerable use, is as follows: 






L + saD 



in which 



V = Velocity in feet per second, 
D = Diameter of tile in feet, 
F = Total fall of drain in feet, 
L = Length of drain In feet. 

Knowing the velocity of flow in a tile of given diameter 
the discharge may be determined by using the general 
formula : 

Q = AV 
in which 

Q = Discharge in cubic feet per second, and 
A = Cross-section area of tile in square feet. 



SIZE OF DRAINS 179 

The number of acres drained is found l)y dividing the 
discharge by a constant representing the number of cubic 
feet per second necessary to relieve one acre of a given 
depth of water in 24 hours. The constants most used 
are: 



0.0052 


cu. 


ft. 


per 


second 


_ 1 

~ 8 


in. 


per 


acre 


in 


24 


h 


nurs 


0.0105 










_ 1 
~ 4 










24 




(C 


0.0140 










1 
— 3 










24 




ii 


0.0210 










_ 1 










24 




a 


0.0315 










3 










24 




ii 


0.0420 










= I 










24 




(( 



In using the formula, the number of acres in the water- 
shed multiphed by the assumed constant may be sub- 
stituted for Q and the formula solved for the diameter of 
the tile. Other methods of computing sizes, such as the 
Chezy-Kutter formula given by Parsons (10), are used. 

Hart (5) has the following to say about the size of drains 
for irrigated lands and construction methods: 

"The spacing of drains in the irrigated section usually 
is much greater than in humid sections and frequently 
a single line of drain may effect the reclamation of a con- 
siderable acreage. From this it will be concluded that 
larger drains will be required in the drainage of irrigated 
lands. It has been found that they need not be propor- 
tionately large, however, since the amount of water which 
it is necessary to take care of is smaller for a given acreage. 
In the arid section, there is likely to be a continuous 
discharge of drainage water throughout the year, and 
frequently the discharge is very uniform at all times. 
However, there are certain maximum flows, usually during 
the period of greatest irrigation application, and it is neces- 
sary to provide a drainage capacity that will take care of 
such flows. 



180 



PRACTICAL DRAINAGE 



"If only the required capacity of the drain were con- 
sidered, it would be found feasible to do a great deal of 
drainage with 4-inch and 5-inch tile, but experience has 
shown that the use of tile smaller than 5-inch is not satis- 
factory, while 5-inch should be used only for short branch 
lines or at the upper ends of branch lines. The following 




26. — Types of Lumber Drains Used to 
Reclaim Boggy Alkali Land. 



table is offered for purposes of comparing the carrying 
capacity of tile lines of different sizes, on the assumption 
that all are laid on the same grade. 



Table XIX. Relative Carrying Capacities of Tile of 
Different Sizes 



One 


Will carry the discharge of 


6-inch tile 


Two 5-inch tiles 

One 6-inch and one 5-inch tile 

Two 6-inch tiles 


7-inch tile 


8-inch tile 




One 8-inch tile and one 7-inch tile 




One lo-inch, one 8-inch, and 5-inch tile; or three 
8-inch tiles; or seven 6-inch tiles; or twelve 
5-inch tiles 





SIZE OF DRAINS 



181 



"As a rule, tile larger than 12 inches in diameter is not 
used in individual farm drainage. 

"The size of tile required depends on the amount of 
water to be carried and on the slope of the drain. The 
latter can be decided upon when the survey of the land 
is made and the fall to the outlet is measured. The 
former is not so easy to determine. It depends on the 
location of the tract, the nature of the soil, the slope of 
the ground both on the tract and above it; on the quantity 
of water used in irrigation and on the method of irrigating, 
both on the tract and on higher land; on the rainfall and 
evaporation; on the seepage from reservoirs, canals, and 
ditches; and on many other factors. Indeed, the de- 
termination of the required capacity of a drainage system 
is the most difficult problem confronting drainage engi- 
neers, and demands their best efforts. Intricate measure- 
ments and calculations must be made in each instance. It 
is therefore impossible to give definite instructions in re- 
gard to this important matter. It is possible, however, 
to give a general idea of required sizes based on a wide 
experience under a great variety of conditions. The fol- 
lowing table is intended to apply to fairly uniform land 

Table XX. Size of Tile Required to Drain Given Areas 
HAVING Different Types of Soil 



Area of 


Size of Tile Required 


Gravel 


(in acres) 


Clay with Sand Stratum 


Sand 


320 
160 
80 
40 
20 
10 


lo-inch 
8-inch 
7-inch 
6-inch 
5-inch 
5-inch 


1 2-inch 

lo-inch 

8-inch 

7-inch 

6-inch 


12-inch 

lo-inch 

8-inch 

8-inch 



182 



PRACTICAL DRAINAGE 



not located at the foot of steeper slopes or benches, nor 
in pockets or depressions, nor in flat river bottoms where 
it will receive surface run-ofl from higher land, nor where 
it will receive water from deep sources by pressure. The 
assumed slope of the tile is 2 feet per thousand feet. 

"If the soil be compact clay, a given size of tile will 
drain larger areas than indicated. If the subsoil be joined 
clay, the 'sand' table should be used. If the drain be 
located at the foot of a bench or in a gravel pocket, none 
of the above bases will apply. A better basis for design 
in such cases is the length of a given size of tile which it 
is safe to use. A slope of 2 feet per 1000 feet is assumed, 
as before. The following table will give a rough idea: 



Table XXI. 


Sizes 


OF 


Tile Required 
Lengths" 


FOR Drains of 


Different 




Size 


OF 


Tile 






Maximum Length 




Sand Stratum 


Gravel 


12-inch 


Fed 

5580 

3350 

1790 

1250 

800 

450 


Fed 

1250 

750 

400 

280 


lo-inch 


8-inch 


7 inch . . 


6-inch . . 


180 


5-inch 









"For greater slopes smaller tile is required, and for 
flatter slopes larger tile is necessary, the variation in 
capacity being as the square root of the slope. If lumber 
boxes are used, the openings should be about the square 
of the tile diameter. 

"For open ditches the bottom width should be 4 feet 
and the side slopes should be at least i to i. Thus for a 
depth of 6 feet the top width would be 16 feet or more, 



CONSTRUCTIOX METHODS 183 

and for a depth of 8 feet the top width would be 20 feet 
or more. 

"In the installation of a drainage system it should be 
borne in mind that the improvement is permanent, and 
that after the tile is once covered up it is more expensive 
to uncover and relay it with larger tile than to install a 
new drain, so it is false economy to cut down on the size 
of tile. It is much better to err on the side of too great 
capacity than too small. 

" Construction Methods. — In man}' instances owing to 
lack of humus the soils of the arid region are very fluxible 
when wet and the construction of drainage systems is v^ry 
difficult and requires painstaking care and ingenuity. 
Special methods and devices have to be employed, and 
special machinery has been developed. 

"Drain hnes must be laid out carefully and grade stakes 
set. The completed drain must be true to grade and as 
straight as possible. For hand trenching it is advisable 
to stretch a cord on the ground along one edge of the 
proposed trench, to obtain good alignment. To insure 
accurate grade at all points, grade plants should be set 
up at each station at a uniform height above the grade of 
the drain. A stout cord then may be stretched over the 
middle hne of the trench from plank to plank and every 
point on this cord will be the given height above grade. 
Grade may be established at one end of each tile with a 
grade pole having a length equal to the distance from the 
cord to the proper location for the tile. This may be 
accomplished by keeping the cord taut by suspending a 
tile or other weight at each end and measuring down 
from the cord at the desired points. 

"Construction work always should start at the outlet 
of each line and proceed up the slope, so that the water 
developed will drain away. 



184 



PRACTICAL DRAINAGE 




Fig. 27. — Wood Drains being Used to Drain Boggy Alkali 
Land. 



CONSTRUCTION METHODS 185 

*'In installing covered drains cither hand labor or trench- 
ing machinery may be used. Frequently, on small proj- 
ects, hand trenching is cheaper, but usually on larger 
projects machines can do the work more rapidly, economi- 
cally, and satisfactorily. It is preferable to let a contract 
for the work to an experienced and capable contractor. 

*'If hand labor is used it usually is necessary to operate 
with small gangs, ordinarily about a half dozen men to 
the line, as the trench must be opened from the top to 
the bottom as rapidly as possible and the tile laid and 
blinded before caving takes place. The men should 
work as closely together as practicable and not even the 
first spading should be taken more than a rod in advance 
of the tile laying. Each man should remove a spading, 
moving backward at the same time. The man removing 
the last spading should also grade the bottom. He should 
not step on the finished bottom and no one should stand 
near the edge of the trench, nor should wagons or material 
of any sort be permitted near the trench. The soil removed 
from the trench should be placed as far back as it con- 
veniently may be. The tile should be laid at once and 
bhnded by means of a few inches of earth caved from the 
edges of the trench. If the banks tend to cave off in 
large chunks or slabs it will be necessary to brace them 
apart with planks separated by stout cross-pieces or trench 
jacks. 

"A very troublesome condition is that in which the 
presence of a wet, pervious stratum near the bottom of 
the trench causes a lateral and upward movement of 
the soil in the bottom of the trench. In such a case it is 
necessary to provide a tight cribbing to shut out the oozing 
material. It consists of two hea\y timbers held apart 
by trench jacks, behind which is driven lumber sheeting 



186 



PRACTICAL DRAINAGE 



properly matched and beveled at the lower ends to insure 
a tight fit. The sheeting may be driven by means of a 
heavy maul and may be removed with a three-legged 
derrick and a special grabhook. 

''If the soil in the bottom of the completed trench is so 
soft that it will not support a man's weight, wooden racks 
or cradles should be laid under the tile to keep it in line 




t,^. *L' 



-jj^TRi'- 



Fig. 28.- 



Drainage Machine with the Digging Wheel above 
THE Ground. 



and on grade. If conditions are exceedingly bad it often 
is advisable to use sewer pipe in place of drain tile, as the 
bells aid in keeping the line intact. Second quality sewer 
pipe is suitable and generally may be purchased at about 
the same price as drain tile. Under ordinary conditions, 
however, the use of sewer pipe is not recommended, since 
the cost of freight and hauling is higher than for drain 
tile and it is heavier and more difhcult to handle. Also, 
in stable ground it is necessary to dig out places for the 
bells, which considerably increases the cost of trenching. 



CONSTRUCTION METHODS 



187 



"Tile should be laid with extreme care. The joints 
should be as close as possible, and if the soil is semi-lluid 
and contains much line sand and silt, it will be necessary 
to pro\'ide some means of keeping the oozing material 
from entering the tile joints. Almost all the water enter- 
ing tile lines makes its way through the joints, practically 
none entering through the walls of even the more porous 




Fig. 



Drainage Machine with ihe J)iggi.\g Wheel in 
THE Trench. 



tile, so the covering for the joints must provide for the 
ready passage of water. Straw makes a very good filter 
when new, but it is likely to decompose and form a sticky, 
impervious mass over the joints. Brush and wallows are 
not satisfactory and render any subsequent removal of 
the tile very difficult. Graded gravel, ranging in size 
from sand to pebbles an inch in diameter, makes an ex- 
cellent filter, but it is not always available. Cinders also 
are satisfactory. Strips of burlap wrapped about the 
joints give good ser\'ice. The custom of laying strips of 
building paper over the joints cannot be commanded, 



188 PRACTICAL DRAINAGE 

since the greatest tendency is for the sand and silt to enter 
at the bottom and if paper is wrapped tightly entirely 
around the joints the water itself will be shut out. For 
genuine quicksand, perhaps the best material is cheese- 
cloth, which should be doubled once or twice and wrapped 
carefully about the joint. This material soon decomposes, 
but in the meantime the soil becomes compacted so that 
the purpose is served. 

"The more pervious materials should be placed adjacent 
to the tile. The backfilling may be done with a plow 
with three or more horses and a long pole evener, or with 
a scraper, road grader, or go-devil. Recently power 
backfillers have been placed on the market. All the soil 
should be returned to the trench and be banked up over it^ 
so that future settling will not leave a depression over 
the drain. 

"In machine trenching it generally is necessary to draw 
a portable shield after the machine in which the tile may 
be laid and bhnded before caving takes place." 

Outlets and Silt Basins. — The efficiency of a drainage 
system may be greatly lessened by an ineffective outlet. 
When the water leaves the drain it should flow away 
freely and not be allowed to back up in the mouth of the 
drain, since this condition causes silt to deposit and finally 
clog the drain. The effectiveness of the drainage system 
throughout its entire length may be lessened by standing 
water at the outlet. If the fall of the land does not per- 
mit of rapid flow from the outlet it may be necessary to 
let the water run into a pit and then pump it out. This 
method is in successful operation at Kearney Park, Cali- 
fornia, in the system described by Weir (13). Here the 
pumps are turned on by an automatic switch operated 
by a float. 



COST OF DRAINAGE 



189 



Provisions should be made to keep stock from tramping 
on the outlet and destroying it. In drains that are dry 
part of the time, screens to keep out rodents and other 
troublesome animals should be placed over the outlet. 

Manholes at intervals in the system assist in locating 
trouble. These manholes may be constructed in such a 




Fig. 30. — Silt Box with Lid. The Silt that 
Settles in the Box can be Spaded Out. 

way that they serve as silt basins and thus eliminate 
from the system silt that might clog the tile. These silt 
basins are particularly necessary if the fall of the drain 
has to be reduced. A good type of combination silt trap 
and manhole is shown in Fig. 30. 

Cost of Drainage. — The cost of installing a drainage 
system varies so much with conditions that definite figures 
cannot be given. Hart (5) estimates the drainage of 
irrigated land to vary from $15 to $30 with $20 as an 



190 PRACTICAL DRAINAGE 

average. If the land is so wet as to require cribbing of 
the trench the cost may run up to $50 an acre or even 
higher. He says that the price of tile may be figured at 
about I cent per inch of inside diameter for each foot of 
length for small sizes and about 2 cents for large sizes. 
Hand trenching costs from 15 to 25 cents a linear foot for 
six feet deep. Machine trenching is considerably cheaper 
but usually costs more than a dollar a rod. The system 
installed at Kearney Park, CaHfornia, with its pumping 
system cost $59.59 an acre, but since it was to be used for 
experimental purposes it was permissible that it be more 
expensive than a system installed by the farmer for strictly 
economic purposes. These figures must all be revised to 
meet post-war prices. 

REFERENCES 

1. Bates, P. H., Phillips, A. J., and Wig, R. J. Action of Salts in Alkali 

Water and Sea Water on Cements. U. S. Bur. Standards, Tech. 
Paper, No. 12 (1912), 157 pp. 

2. Brown, C. F. Farm Drainage. A Manual of Instruction. Utah 

Sta. Bui. 123 (1913), pp. 5-55. 

3. Brown, C. F., and Hart, R. A. The Reclamation of Seeped and 

Alkali Lands. Utah Sta. Bui. iii (1910), pp. 75-91. 

4. Burke, E., and Pickney, R. M. The Destruction of Hj^draulic Cements 

by the Action of Alkali Salts. Mont. Sta. Bui. 81 (1910), pp. 41-131. 

5. Hart, R. A. The Drainage of Irrigated Farms. U. S. D. A. Farmers' 

Bui. 805 (191 7), 31 pp. 

6. Headden, W. p. Destruction of Concrete by Alkali. Colo. Sta. 

Bui. 132 (1908), pp. 3-8. 

7. Jeffery, J. A. Textbook of Land Drainage, 502 pp. (New York, 

1916.) 

8. King, F. H. Irrigation and Drainage, 502 pp. (New York, 1899.) 

9. Meade, R. K. Experiments on the Action of Various Substances on 

Cement Mortars. Engin. Rec. 68 (1913), pp. 20-21. 

10. Parsons, J. L. Land Drainage, 159 pp. (New York, 1915.) 

11. Sims, C. E., and Dieckman, G. P. Investigation of the Effects of 

Alkali on Concrete Drain Tile near Lake Park, Iowa. Concrete- 
Cement Age, 6 (1915), pp. 278-281. 



REFERENCES 191 

12. Steik, Karl. The KO'cct of .\lkali upon rorlland ("emt'iit. Wyo. 

Sta. Hill. 113 (1917), i)p. 71-122. 

13. Whir, W. \V. Preliminary Report on Kearniy Xineyard ICxperi- 

menlal Drain, ("al. .Sta. Bui. 273 (igiO), |)p. 103-123. 

14. Wic, R. J., and Williams, G. M. Investigation on the Durability 

of Cement Drain Tile in Alkali Soils. U. S. Bur. Standards, Tech. 
Paper, No. 44 (1915), 56 pp. 

15. WiLLCOCKS, Wm. Egyptian Irrigation, Chapter \TII, pp. 229-254. 

(London and New York, 1899.) 

16. YoHE, H. S. Organization, Financing, and Administration of Drain- 

age Districts. U. S. D. A. Farmers' Hul. 815 (191 7), 37 pp. 



CHAPTER XIV 
CROPS FOR ALKALI LAND 

Plants differ greatly in their resistance to alkali. Certain 
crops, such as the beet, will withstand very large quantities 
and still produce good yields, whereas others, like blue- 
grass, resent even comparatively small quantities of any 
alkali salt. It is therefore of great importance to choose 
the proper type of plant for the particular conditions. 

Factors Affecting Resistance. — Certain fundamental 
problems such as the nature of the alkali-resistant plants, 
the nature of the soil, climatic conditions, and economic 
considerations, should be carefully studied before deciding 
finally on which crop to plant. Perhaps the first thing to 
consider is the difficulty in getting the plants started in 
the alkali soil. Some of the best crops for alkali resistance 
when once started well, of which alfalfa and beets may 
be taken as examples, must be planted shallow and if the 
alkali tends to concentrate at the surface during their 
tender seedling stage, it is very difficult to secure a stand. 
If, however, the alkali can be kept below the feeding zone 
of such plants by washing or in other ways while they get 
a start, satisfactory crops can be secured. As alkah is 
not so concentrated when the soil is kept well moistened, 
this condition should be sought while the plants are young. 
Some varieties of each crop are best suited to resist alkali 
during the seedling stage; hence it is important to choose 
seed from successful crops on similar soils where possible. 

The character of the root system of different plants 
needs consideration. Shallow-rooted crops, like the cereals 

192 



FACTORS AFFKCTING RESISTANCE 193 

and most cultivated grasses, may fail to give a satisfactory 
crop because the alkali tends to concentrate near the 
surface if evaporation is active. This accumulation makes 
the salts very strong throughout the feeding zone of the 
plant and, therefore, toxic even when the total quantity 
of salts in the upper three or four feet is rather small. 
Deep-rooted plants, like alfalfa and trees, may penetrate 
the alkali strata by growing in the upper soil while the 
alkaH is beneath and gradually feeding lower as the alkali 
accumulates at the surface. In this way some plants not 
exceptionally tolerant may withstand what seem to be 
excessive quantities when the whole feeding zone is not 
considered. Where alfalfa, cotton, and other deep-rooted 
plants get a good start but encounter a strong alkali 
stratum at a short distance below, these plants may prove 
less resistant than the cereals which may feed in the upper 
less alkaline soil. The latter condition is especially marked 
when alkah is accompanied by a hardpan or heavy clay 
subsoil. The same may also be said of soils that are under- 
lain by a shallow water-table, pasture or meadow grasses 
and grains making much better crops than the deeper, more 
resistant crops. 

Another important factor is the resistance of the plants 
to reclamation methods. A few crops, among which are 
alfalfa after once well started, sorgo, rice and berseem 
clover, can endure the frequent heavy irrigations that may 
accompany reclamation. The best crop of course depends 
on the particular conditions, alfalfa doing well with good 
drainage but not in a soil containing excessive quantities 
of water, whereas some of the other crops like sorgo may 
do best where drainage is not so good. During the re- 
clamation process it is a great aid to have the land shaded 
or cultivated in order to prevent alkali from rising. Alfalfa 



194 CROPS FOR ALKALI LAND 

and other plants which shade the soil during the great 
part of the season are preferable to those like grain which 
leave the land unshaded during spring and again during 
fall. Beets, fruits, and other crops that are grown in 
rows and require cultivation are useful because of the 
mulching, which helps check surface accumulations of 
alkali. For this purpose it is better to have annual crops 
which allow the ridges to be leveled down occasionally 
than perennials which allow alkali to accumulate at the 
top of the ridges year after year instead of being washed 
out of the soil. 

The nature of the soil also has some influence on the 
choice of crops. With a lifeless clay it is preferable to 
grow some crop such as rye rather than one Hke beets 
which requires considerable organic matter and much 
working of the soil to produce a satisfactory crop. It is 
frequently profitable to raise rye as a green manure crop 
to improve the soil conditions before a more exacting 
crop is grown. A soil without good drainage and where 
artificial drainage is impractical may often be planted to 
some of the more resistant forage or meadow grasses which 
will endure water-logged conditions. Soils with con- 
siderable organic matter are frequently more moist and 
the alkali apparently less toxic than in the ordinary alkali 
soil so that more profitable and less resistant crops may 
prove best. 

It is unfortunate that the most tolerant cultivated crops 
are not well adapted to grow in the climate of most parts 
of the United States where alkali is found. The date 
palm, which is perhaps the most tolerant crop for soils 
containing chloride and sulphate salts, rice, cotton, ber- 
seem clover, and several other desirable crops are adapted 
only to the warmer alkali regions. Australian salt-bush, 



ECONOMIC FACTORS AFFECTING CHOICE 195 

which withstands hirgcr (juaiitities of alkali than ahnost 
any other desirable alkah-resistant plant, does not do well 
where winters are severe. 

Economic Factors Affecting Choice. — After knowing 
the relative tolerance of the various crops and their adapt- 
ability to the particular conditions, certain economic 
considerations further modify the choice. With cheap lands 
in some of the grazing sections, for instance, it might be 
preferable to plant the land to some permanent grass 
giving only a medium yield than to use the more resistant 
crops such as sugar-beets and other high-yielding plants 
which do best under certain other economic conditions. 
As a general rule, forage crops are more suited to alkali 
lands than crops in which quality is more important. 
Land in the neighborhood of large cities or other places 
where there is a good market for intensive crops, such as 
the vegetables and fruits, is often more economically 
planted to these crops even though they may be somewhat 
less tolerant of alkali than other crops. 

The use to be made of the crops also governs the choice 
for alkali lands. Grain crops will produce a heavy growth 
of fairly good hay in soil considerably too strong to give 
satisfactory yields of grain. Likewise, although cotton 
grown upon certain kinds of alkali lands does not give 
the line-textured liber so desirable in the manufacture of 
the high-class cotton goods, it may produce a profitable 
yield of the coarser grade suitable for other purposes. 
Sugar-beets will produce excellent yields of roots on land 
that is high in alkali, but if the quantity of salts, especially 
sodium chloride, be too large the beets may be so poor in 
quality that they are lit only for stock feed and not for 
sugar-making. The quality of sugar cane and of various 
fruits is impaired when grown upon soils impregnated with 



196 CROPS FOR ALKALI LAND 

certain kinds of alkali, but as long as the yield is sufficiently 
high to prove economical when used for any purpose con- 
ditions may warrant the use of such a crop in preference 
to crops not injured materially by the alkali but which 
do not fit economically into the cropping system. 

Where the main object is to reclaim land quickly and 
put it in condition for the common crops, it is frequently 
desired to green manure the land, to get good aeration of 
the soil, to retain a mulch, and to keep all moisture moving 
downward. For such purposes where the soil contains 
salts in quantities so large that most ordinary crops fail, 
sorgo, rye, millet, barley, rape, kale, and a few other high- 
resistant crops which yield a large quantity of dry matter 
are used. When the alkali content does not exceed about 
5000 parts per million of white alkali, less resistant but 
more desirable legume crops (sweet clover, alfalfa, Canada 
field peas, vetch, and horse beans) should be preferred to 
the above crops, provided the seed-bed can be prepared 
so that a good stand may be secured. 

Tolerance of Alkali by Various Crops. — In studying 
the figures given for the quantities of salts that various 
crops have been found to endure safely, it should be kept 
in mind that the character of the plants, feeding system 
in relation to the alkali, and the nature of the soil as above 
mentioned will often cause enormous differences with the 
same plant. Soil, moisture, climate, and perhaps other 
things will often change the relative tolerance of the dif- 
ferent crops to some extent so that slight differences in 
tolerance mean httle or nothing. Unless otherwise men- 
tioned, the salt as given is understood to be the proportion 
found in the soil to a depth of four feet. Although this 
arbitrary unit will be misleading when the concentration 
of the salts varies at different depths in the soil, as is often 



FORAGK CROPS 197 

the case, it is the most satisfactory method available for 
comparing the different crops as a whole. Not only is 
the root system of most ordinary crop plants within the 
four-foot zone, but also this is the region where a large 
part of the alkah is concentrated. On most alkaH lands 
the salts in the first four feet of soil may be drawn toward 
the surface where they will concentrate. 

Forage Crops have given more satisfaction for use on 
rather strong alkaline soils than other cultivated crops as 
a general rule. Quality in fruit, vegetable, sugar, fiber, 
and grain crops is frequently so impaired by alkali that 
the crop is practically worthless for the product ordinarily 
obtained, but since quantity is the chief requisite for forage 
the crop serves its purpose when a good yield is obtained. 
Leguminous plants as a family are very sensitive to alkali, 
especially sodium carbonate. Hilgard (12) states that 
alkali even when present in quantities as small as 200 or 
300 parts per million is generally harmful to most of the 
legumes. Alfalfa and sweet clover, especially the latter, 
however, are among the crops generally recommended as 
being resistant to alkali. 

Alfalfa sometimes fails to give satisfactory results on 
alkali land because it is rather sensitive in the seedling 
stage. A good stand and healthful growth in its first 
stages are sometimes secured by driving the alkali below 
the seed-bed by means of a heavy irrigation. Hilgard 
places the limit for unaffected growth at about 1650 parts 
per million total salts, about 300 parts per million of 
sodium carbonate, or about 1390 parts per million of sodium 
sulphate. Kearney (17) places the highest successful 
amount at 4000 parts per million of white alkali, while 
Means and Gardner {22) state that 4000 parts per million 
of white alkali caused young alfalfa to become sickly or 



198 CROPS FOR ALKALI LAND 

unhealthy. It is a very sensitive plant to black alkali 
when in the seedling stage. 

The limits for an old stand of alfalfa range between 
20OO and 7100 parts per million of total salts, according to 
the various authors. The lower of these limits was for a 
sandy soil, and Sanchez (25) states that on a loam soil a 
higher concentration may successfully be withstood. That 
the crop should produce a heavy mature crop on soil 
containing 7100 parts per million, most of which was 
sodium chloride, might have been due to the fact that there 
was standing water at a depth of four feet and that the 
salt was considerably diluted by the moisture. Most 
estimates place the limits between 3000 and 4000 parts 
per million of w^hite alkali. 

With black alkali, or sodium carbonate, the observa- 
tions on old alfalfa land vary between 300 and about 900. 
These differences are partly due to the differences in the 
nature of the soil and to the different methods of determin- 
ing and expressing the results of the analyses. As this 
salt is generally found in connection with other alkali 
salts the limit can hardly be expected to be a definite 
quantity even in soils of like character. Likewise, the 
quantity of sodium chloride and sodium sulphate endured 
successfully vary through a wide range modified by the 
presence of other salts. Where the salt was mostly sodium 
chloride, the variation assigned by the authorities ranges 
from 2000 parts per million on a sandy soij to 7100 parts 
per million on a loam soil well supplied with moisture. It 
is probable that on a loam soil handled so as to protect it 
from accumulation of alkali when the crop is not shading 
the ground and kept well irrigated will support a satis- 
factory growth of alfalfa when it contains as much as 4000 
parts per million of sodium chloride. On a sandy loam 



SWEET CLOVER 199 

in Montana Neill (23) reports a diminished }icld where the 
alkaU content was about 4000 parts per milhon, mostly 
of sodium sulphate, while Kearney (17) places the highest 
quantity under which alfalfa will succeed at 6000 of this 
salt. Very few important crops will grow with larger 
quantities of these alkalies in the soil. In most soils, 
there is a mixture of the salts in various proportions so 
the limits of the separate salts serve only for general 
purposes. The high resistance of alfalfa may be assigned 
to its deep feeding habits in many cases, the feeding roots 
not being in the alkali zone but being in the purer solu- 
tions below. 

Sweet clover {Melilotus alba and M. officinalis) is widely 
recommended for alkali lands. It is as resistant as alfalfa 
and is often preferred to alfalfa for alkali land. Coe (i) 
states that it will withstand so much black alkah that 
salt grass is the only other crop that can compete with it 
on this kind of land. It gives more satisfaction than 
alfalfa on alkali lands which are water-logged or have a 
shallow water-table. Sweet clover is not ordinarily so 
satisfactory a forage crop as alfalfa because it is necessary 
to reseed it every alternate year, whereas alfalfa yields 
well for years. It is so difficult to secure a good stand 
of these crops under alkali conditions that it is very de- 
sirable to have a continuous or perennial crop. Sweet 
clover is easier to get started on alkali land than alfalfa. 
It requires more care in harvesting because if it is allowed 
to grow too long it acquires a disagreeable flavor and it is 
not so readily eaten as alfalfa. The few observations on 
the resistance of sweet clover to alkali show it to rank 
about with alfalfa, so that other conditions being equal 
alfalfa is the preferable crop. However, on water-logged 
land or where alfalfa does not thrive for other reasons, 



200 CROPS FOR ALKALI LAND 

and where the crop is desired more as a means of reclaiming 
the land for other crops in a few years, sweet clover is 
preferable. It is an excellent green manure to be used in 
upbuilding alkali land. 

Other Clovers. — The only other clover that has been 
found to do well in the presence of large quantities of alkali 
is berseem, or Egyptian clover. It has been found to 
endure 4000 to 6000 parts per million of alkali, mostly 
sodium chloride, under Egyptian conditions, but it has not 
been used to any extent in this country. It requires mild 
winters and is sensitive to cold. In Egypt it finds favor 
in reclaiming alkali land because it withstands flooding 
and an excessive water content of the soil which accompany 
reclamation methods. Loughridge (19) found the limit 
for burr clover to be about 1 130 parts per million of black 
alkali, which is exceptionally high for this salt. Crimson 
clover and Birdsfoot clover both withstood 530 parts per 
milHon, and white clover 630 parts per million of black 
alkali according to this author. Red clover was not found 
growing in concentrations greater than 670 parts per milUon 
of total salts. 

Vetch ( Vicia saliva and V. villosd) has met with consider- 
able favor in certain districts because it germinates well 
on land which will not give a good stand of other resistant 
crops without considerable trouble. Kearney (17) places 
the limit for good germination between 4000 and 6000 parts 
per million of white alkah, and Loughridge (19) found it 
growing unaffected in a soil containing 4340 parts per mil- 
lion of total salts, 160 parts per million sodium carbonate, 
200 parts per million sodium chloride, and 3980 parts per 
million of sodium sulphate. It may be used for- pasture 
or as a green-manuring crop, but since it does not do so 
well under most alkah conditions and since other crops 



LEGUMES 201 

such as sweet clover mcel the conditions better it has 
found httle use on alkaU lands. 

Field peas {Pisum stavium) are said by Kearney (17) to 
germinate and produce normal seedling growth in the 
presence of 2000 parts per million of white alkali, mostly 
sodium sulphate. He states that a good crop of peas can 
be grown in the presence of 4000 parts per million of this 
type of alkali, but that this quantity is near the upper 
limit for the seedlings and consequently a poor stand 
might be expected. 

Beans are ordinarily considered to be rather sensitive 
to alkali, but Kearney (17) classifies broad beans as pro- 
ducing pods in the presence of 4000 parts per million 
of white alkali. They are sometimes grown as a green ma- 
nure on alkali lands but have not found much favor because 
other crops are better adapted both on account of climatic 
conditions and because other crops produce more forage. 
The seed being large, germination is better than with 
most legumes, but w^here the growing season is not cool 
the growth is not satisfactory. Neill (23) considers 2000 
to 4000 parts per million of alkali, mostly sodium sulphate, 
as being too much for the seedling stages of beans, but 
states that 2000 parts per million or less will allow all 
ordinary Wyoming crops to do well. 

A number of other leguminous plants, including lupines, 
lentil, esparcet, and other minor forage plants, have been 
studied under alkali conditions by Loughridge in Cali- 
fornia (20), but none have given promise of competing 
with alfalfa and sweet clover. 

Grasses. — True grasses are as a family more resistant 
than the legumes. Some of the wild varieties, such as salt 
grass and tussock grass mentioned in Chapter VI, rank as 
the most resistant plants known. The cultivated grasses 



202 CROPS FOR ALKALI LAND 

are generally more sensitive than the wild ones. Observa- 
tions of the more important meadow and pasture grasses 
have been made, but the number of different conditions or 
combinations of salts under which they have been studied 
makes the limits indicated for them of less value than for 
plants which have had a larger number of studies made 
of them. 

Timothy {Phleum pratens) is reported by Kearney (17) 
to succeed in the presence of 4000 to 6000 parts per mil- 
lion of white alkali and perhaps more where the dis- 
tribution of alkali is uniform. Traphagen (29) places the 
limit below 10,000 parts per million where the salts are 
mostly of the sulphate type. Near Baker City, Oregon (3), 
an average crop was produced on land containing 700 parts 
per million of sodium carbonate. Timothy, like almost 
all of the grasses, has very small seed, and it is very im- 
portant in getting a stand with such seed that the seedbed 
be free from alkali. Unless the alkali can be washed out 
of the seedbed until the grasses get a good start, it is al- 
most useless to seed these crops on alkali land. Timothy 
can be kept moist throughout the year, and because keep- 
ing the soil moist dilutes the alkali the growth is much 
more satisfactory than where less water is used. 

Orchard grass {Dactylis glomerata) is probably a little 
more resistant to white alkali than timothy. Kearney (17) 
places the limit for successful growth between 4000 and 
6000 parts per million for the white type of alkali. In 
California the highest alkali in which it was found growing 
unaffected was 1260 parts per million total salts, 580 parts 
per million of sodium carbonate, and 550 parts per million 
sodium sulphate. 

Brome grass (Bromus inermis) is one of the most resistant 
of the tame grasses. It has been found (17) to grow un- 



GRASSES 203 

hindered in the presence of as much as 5000 parts j)er mil- 
Hon of white alkah and to make a good growth and pro- 
duce seed with 7000 parts per milHon. In California (20) 
it was unaffected with 3170 parts per milhon of total salts, 
630 parts per milhon of sodium carbonate, 230 parts per 
milhon of sodium chloride, or 2230 parts per million of 
sodium sulphate. This is one of the best pasture grasses 
of the western part of the United States where the land is 
not kept too wet. 

Red top {Agroslis alba) has not been tried extensively 
under alkali conditions but Kearney (17) reports it to 
succeed in the presence of 4000 to 6000 parts per million 
of white alkali and to do better than timothy or orchard 
grass. It grows well on excessively wet lands, lands too 
wet for even timothy, and in such land can probably 
withstand as much alkali as any of the important culti- 
vated grasses. 

Blucgrass (Poa pratensis). — ^ In CaHfornia bluegrass 
withstood successfully 670 parts per million of total salts', 
380 parts per million sodium carbonate, and 220 parts 
per milHon of sodium sulphate. It is ordinarily regarded 
as very sensitive to alkali and this apparently shows 
it to be one of the most tender tame grasses. In rather 
extensive tests made by Harris and Pittman (7) it was 
found to be the most nonresistant crop under investigation. 

Western wheat grass (Agropyrou) may be regarded as one 
of the most resistant grasses, as it can be grown success- 
fully upon soil containing at least 6000 and 8000 parts 
per million. It is very difficult to get started because of 
low germination of the seed. The lack of popularity is 
partly due to this difficulty of getting a start. 

Japanese wheat grass (Agropyron japonicum) was found 
by Loughridge in Cahfornia (20) in the presence of 2330 



204 CROPS FOR ALKALI LAND 

parts per niillion of total salts, 840 parts per million of 
sodium carbonate, 820 parts per million of sodium chloride, 
or 820 parts per million of sodium sulphate. 

Rye grass is one of the favorite grasses of Italy and 
England, but it has not met with much favor in this country 
except in a few places on the Pacific Coast. Italian rye 
grass {Lolium italicum) is said by Kearney (17) to succeed 
in soil carrying 6000 to 8000 parts per milhon of white 
alkali. Other observations indicate it falls considerably 
below this quantity, however. Shutt (26) found a good 
growth with 1387 parts per million of total salts, 900 parts 
per million of which was sodium sulphate, and Lough- 
ridge (20) places the limit at 1090 parts per million of 
total salts, 580 parts per million sodium carbonate, 120 
sodium chloride, or 640 parts per million sodium sulphate. 
The latter author gives 1410 as the limit for good growth 
on English rye grass {Lolium perenne). 

Fescue, like rye grass, is an important grass of Europe 
but has not been able to compete with the other forage 
crops in this country. Kearney (17) regards it as more 
resistant to alkali than most cultivated grasses, the limit 
being between 6000 and 8000 parts per million of white 
alkali. It is hard to get started and therefore rather 
unsatisfactory where the more profitable grasses can be 
grown. Observations by Loughridge (20) indicate the 
different varieties to resist from 11 90 parts per million to 
2180 parts per million of total salts, up to 630 parts per 
million of sodium carbonate and up to iioo parts per 
million of sodium sulphate. Meadow fescue {Fescue 
pratensis) was found by the latter to be adapted to alkali 
land. 

Tall meadow oat-grass {Arrhenatherum elatins) is another 
European grass not grown to any extent in this country, 



GRASSES 205 

but it seems to withstand rather large quantities of alkali. 
Growth was unhindered in a soil containing 5000 parts per 
million of white alkali and a good growth was found where 
7000 parts per million were present according to Kearney 
(17). He regards it as about equal to brome grass in 
alkali resistance, or slightly below western wheat grass. 

A number of new or minor grasses have been tried on 
alkali lands in California, but none of them have proved 
close competitors of the higher-producing standard grasses 
of the United States, such as timothy and alfalfa. 

Wild or native grasses are frequently found growing on 
soil which is very high in alkali. These grasses seldom do 
well in pastures or meadows and generally do not produce 
very large quantities of feed. ]\Iany of them are hard to 
get started on new land; their value is likely to be mainly 
as range grasses of poor pastures on highly alkaline soil. 

Salt grass {Distichlis spicata) is probably the most im- 
portant of the native grasses. It occurs throughout the 
world under a great variety of conditions. It was observed 
in the Bear River Valley, Utah (16), growing on soil con- 
taining from 30,000 to 50,000 parts per million of salts, 
a large part of which was sodium chloride, and yet it does 
well in soils containing practically no salt. It shows 
hardly any preference for the t}'pe of alkali nor the con- 
centration. It has been found growing apparently unaf- 
fected on land charged with 8516 parts per million of sodium 
carbonate (13), a quantity so great that hardly any other 
kind of vegetation could survive. Of course where the 
nature of the soil is unfavorable, these large quantities of 
salts would be too great for the plants to do well, but most 
alkali land does not contain excessive quantities of salts 
for this plant. It produces little seed so that It is very 
difficult to propagate artificially and it is seldom planted. 



206 CROPS FOR ALKALI LAND 

Blue-stem grass {Agropyron occidcntalc) was found grow- 
ing in a Montana soil (29) containing in the surface foot 
320 parts per million of sodium carbonate, 1649 parts per 
million of sodium chloride, and 24,080 parts per million 
of sodium sulphate. The average for the upper four feet 
was 384 parts per million of sodium carbonate and 10,360 
parts per million of sodium sulphate. There was a good 
growth of mLxed grass, mainly blue-stem, in this 
meadow (29). 

Tussock grass, or purple top {Sporoholus airoides), men- 
tioned in Chapter VI as an alkali-indicating plant, with- 
stands very large quantities of alkali. It is relished by 
stock but will probably not do well except on the ranges. 

Alkali meadow-grass {Puccinellia airoides) (24), also 
mentioned in Chapter VI, may furnish good browsing 
for stock and if available at the proper time it may furnish 
profitable hay on moist alkali lands. 

Prairie grasses were observed by Shutt and Smith (26) 
in Canada to withstand 700 parts per million of sodium 
sulphate in the upper 6 inches of soil even where the soil 
beneath this held over 6000 parts per million and the upper 
3 feet averaged 6717 parts per million. Where the upper 
6 inches of soil contained 4320 parts per million of sodium 
sulphate and the average for the upper 3 feet was 9773 
parts per million of total salts, there was a poor growth, 
however. 

Modiola {Modiola procumbens), a weed introduced into 
California from Chile, is reported by Loughridge (20) to 
withstand 13,100 parts per million of total salts, composed 
of 1 1 90 parts per million sodium carbonate, 10,210 parts 
per million sodium chloride, and 1700 parts per million of 
sodium sulphate in the upper foot of soil. It has been 
found to make an acceptable pasture where alfalfa could 



GRASSES 207 

not be started well. Were it not for the fact that it is a 
troublesome weed where not wanted, it would probably 
lind more fa\or as a pasture grass. < 

Sall-biishcs {Aln'plcx spp.), as noted in Chapter VI, 
make an acceptable forage where the land is too alkaline 
to permit successful growth of the better classes of forage 
plants. There have been a number of attempts to intro- 
duce these plants as cultivated crops for alkali land. The 
Australian salt-bush (especially A. semihaccaia) is said to 
be well adapted to California conditions and to be easily- 
propagated. Hilgard (13) regarded it as being one of the 
most promising forage crops for alkali lands, being a quick- 
growing and high-yielding plant as well as producing hay 
which is readily eaten by all animals. It is not adapted 
to climates with severe winters nor to places frequented by 
summer fogs. It would be of little value outside of a mild 
climate. Other varieties of salt-bushes have been tried for 
the more severe interior country and, although where once 
started, they yield a fairly large quantity of good forage, 
these plants have received almost no recognition in a 
practical way. They are so difficult to get started that 
farmers will not take the trouble to plant them. 

Giant rye-grass {Elymus condcnsatus) is reported b}- 
Hilgard (12) as being in about the same class as tuasock 
grass for alkali resistance (3000 to 31,000 parts per million 
— tussock). In its wild state it grows in large clumps, 
but where sown at the rate of about twenty-five pounds 
per acre it makes a rather uniform growth of coarse but 
palatable grass or hay for sheep or cattle. When grown 
on alkali land it generally contains considerable salt which 
makes it somewhat laxative for horses. Although it is 
at present not receiving much attention as a cultivated 
crop, it should occupy more of the soils containing too 



208 CROPS FOR ALKALI LAND 

much alkali for alfalfa, and similar crops. Being a large 
yielding grass, it is grown as a hay crop on some of the 
less desirable lands of Oregon and Washington as well as 
a few other places. 

Sedges and rusJies frequently form the main growth of 
alkali swamps or low moist lands. The tuber bulrush 
(Scirpus paludosus) is recommended by Nelson (24) as 
being the best of these plants for forage on alkali lands of 
the moist type. 

Millets, especially the stout rooted varieties, are among 
the resistant cultivated grasses. Common, or foxtail 
millet {Chaltochloa italicd) is classified by Kearney (17) 
as withstanding 6000 to 8000 parts per million of white 
alkali, a good crop usually being secured where not more 
than the lower quantity is present and a fair crop between 
the two points or even a little above. Barnyard grass 
{Panicum crus-galli) resists white alkali fairly well ac- 
cording to Hilgard (13). Proso, or broom-corn millets, 
{Panicum miliaceum) will produce a good crop in the 
presence of less than 4000 parts per million of white alkali, 
but since other crops are usually more profitable with this 
quantity, and since an excess of alkali is likely to reduce 
the yield of grain to an unprofitable point, its value on 
such lands is questionable. Loughridge (20) found Egyp- 
tian millet {Elusine coracana) growing unaffected in the 
presence of 1140 parts per milHon of total salts, 580 of 
sodium carbonate, and 480 of sodium sulphate, and many- 
flowered millet {Milium multijlormn) in the presence of 
1090 total salts, 210 sodium carbonate, 120 sodium chloride, 
and 440 parts per million of sodium sulphate. Other millets 
that were tested resisted less than 1000 parts per million. 

Sorghums are rather resistant, can endure flooding, and 
are readily cultivated so that they are among the better 



RAPE 209 

crops for reclaiming alkali lands. If the soil can be kept 
moist by irrigation while the plants are in the seedling 
stage the crop apparently does not suffer. Kearney (17) 
places the limit for the saccharine sorghums between Cckx) 
and 8000 parts per million of white alkali or for an almost 
assured crop just below these points. He states that 
these sorghums are among the most resistant plants when 
in the seedling stage. An Hawaiian (5) experiment showed 
cane to endure 3357 parts per million of alkali, mostly 
sodium chloride, the growth being unchecked when the 
roots of the plants were drawing from free water, but that 
when the moisture content of the soil fell to 28 per cent 
there was no growth on a soil containing 1980 parts per 
million of this salt. The highest quantities of alkali on 
which Loughridge (19) found sorghum growing unaffected 
w'as 5100 parts per million of total salts, 620 parts per 
million of sodium carbonate, 610 parts per milhon of 
sodium chloride, and 3870 parts per million of sodium 
sulphate. These limits show that where sorghums are 
adapted they may be expected to grow on soil too strongly 
alkaline to permit most ordinary crops to survive. 

Rape {Brassica napiis and B. olcracca), while practically 
unknown to the farmers of the United States, is a rather 
alkali-resistant crop which is extensively used for forage 
in Europe. The seedling of this crop is very delicate or 
sensitive to alkali and there is difficulty with the stand 
where a crust is formed before the plants break through 
the upper soil. By keeping the soil moist and pa}T[ng 
close attention to the seedlings little attention will need 
to be given rape on account of alkali thereafter. The 
plants withstand, and make a fair growth w^ith, as much 
as 600c to 8000 parts per million of white alkali and will 
grow practically unchecked with 4000 parts per million, 



210 CROPS FOR ALKALI LAND 

according to Kearney (17). This crop is not well adapted 
to the present economic conditions of the United States 
and it is too troublesome in its seedling stage to gain popu- 
larity with the American farmer. 

Grain crops have been tried under a great variety of 
alkali conditions both as a grain and a forage crop. They 
may successfully produce forage or green manure on land 
too strongly impregnated with alkali to yield grain profit- 
ably. During hot weather, unless the moisture conditions 
are favorable, grain is likely to become shriveled and hard 
where the so* contains considerable alkali. Under certain 
other condi„.ons the alkali may cause the plants to spend 
most of their energy in leaf production rather than seed. 

Wheat has been grown for hay on land too strong for 
alfalfa to either germinate or grow (27). According to 
Kearney (17), the highest quantity of white alkali per- 
missible for the successful production of wheat hay was 
4000 to 6000 parts per million, while for a grain crop it 
could successfully endure only 1000 to 4000 parts per 
million. The author (6), however, found wheat doing 
moderately well as a grain crop where the top foot of soil 
contained 8756 parts per million of total salts, 1146 parts 
per million of sodium carbonate, 1577 parts per milHon of 
sodium chloride, and 5840 parts per million of sodium 
sulphate, the average salt content of the top four feet of 
soil being 11,829 parts per million of total salts, 11 21 
parts per million of sodium carbonate, 2334 parts per 
million of sodium chloride, and 7512 parts per million of 
sodium sulphate. These quantities are the average of 
determinations in four different fields in different sections 
of Utah; enormous quantities of sulphates amounting in 
some cases to 20,000 parts per million were found in soil 
growing wheat, but where sodium chloride became a promi- 



GRAIN CROPS 



211 



nent salt Ihc (|uantity was much less. Observations b\^ 
Shutt and Smith (2O) show that on a loam soil with a 
heavy clay subsoil, wheat made a good growth where the 
upper six inches of soil contained practically no alkali 
salts, but the next foot contained 1780 parts per million, 
and below this over 8000 parts per million of salts most 
of which was sodium sulphate. When the upper sLx 
inches contained 1230 parts per million of salts and the 




^'''^•^*^:* -^#1^^ 



Fig. 31. — Alkali Spot in a Grain Field. 

soil beneath this 7000 parts per million the growth was 
poor, apparently showing that the upper six inches of soil 
was the injurious portion. In the Bear River Valley, 
Utah, Jensen and Strahorn (16) found wheat doing well 
in a soil the top foot of which contained 5000 to 5600 parts 
per million of alkali, mostly sodium chloride. Lough- 
ridge (19) places the limits for unaffected growth at 1520 
parts per million total salts for Gluten wheat and 1080 for 
ordinary wheat. 

For sodium carbonate Headden (8) states that 400 parts 
ner miiiion in the soil will prove injurious to wheat, while 



212 CROPS FOR ALKALI LAND 

Jensen and Mackie (15) place the limit of profitable pro- 
duction below 500 parts per million. The quantity of 
sodium chloride that may be tolerated without notable 
injury to wheat has been placed at from 100 to about 
5000 parts per million by the various investigators. Few 
observations have been made where sodium chloride or 
sodium sulphate were the main salts. Traphagen (29) 
states that the danger limit for wheat when the salts 
consist of sulphates, two-thirds sodium sulphate, and the 
rest magnesium sulphate is about 10,000 parts per million. 
Considering only the sodium sulphate, this estimate is 
nearly the same as the figures of Shutt (26) and the au- 
thor (6), but much above these of Loughridge (19). It is 
probable that the great discrepancies shown in these ob- 
servations are partly due to a number of factors such as 
the nature of the soils, mixtures of the salts, and feeding 
zone of the roots. The variety of grain, as indicated in 
the seedling tests noted in Chapter V, would probably 
have some influence but not so much as the figures indicate. 
Barley is the high-yielding grain of the West which 
corresponds to corn in the central states. It is commonly 
looked upon as being the most tolerant of the ordinary 
grains for alkali. A number of observations have in- 
dicated that this crop grows practically unhindered with 
2000 to 4000 parts per million of white alkali and that it 
frecjuently produces a good crop of grain with as much as 
6000 parts per million of white alkali in the soil. When 
grown as a forage crop, there will be a satisfactory yield 
when the soil contains from 6000 to 8000 parts per million, 
provided the seedbed is kept fairly free at first, according 
to Kearney (17). Jensen and Mackie (15) found a poor 
stand of barley on soil containing 500 parts per million 
of sodium carbonate, but Holmes (14) states that this 



GRAIN CROPS 213 

quantity will be withstood fairly well. Loughridgc (19) 
found it to do well in the presence of 740 parts per million 
of sodium carbonate. Although Dymond and Houston (4) 
state that barley was growing on soil having been flooded 
by sea water and containing 16,000 to 20,000 parts per 
million of salt in the upper six inches of soil, it is probable 
that the plant roots were not feeding in the zone contain- 
ing the salts. It withstands black alkali better than 
wheat. The highest sodium chloride content of soil 
that barley has been observed to tolerate unaffected was 
640 parts per million in a California soil (19) which also 
contained other salts. Traphagen (29) places 10,000 
parts per million of sulphates as the danger limit for 
barley where two-thirds of this was sodium sulphate. 
Barley should be more important as an alkali land crop. 
Oats are generally considered to be intermediate between 
wheat and barley in alkali resistance. Kearney's obser- 
vations (17) indicate wheat and oats to be about equal 
in this respect, but most others show oats to be the more 
tolerant, especially of sodium carbonate and sodium 
chloride. The author (6) found 5000 to 10,000 parts per 
million of total salts in the upper foot and 6000 to Sooo 
parts per million for the average of the top four feet in 
soils producing a medium crop of oats. Others indicate 
much less than this to have caused serious trouble. A 
very wide difference is noted for the effect of sodium car- 
bonate, but it appears that from 600 to 700 parts per mil- 
lion of this salt is as much as is safely withstood. No 
figures are available for the tolerance of oats to sodium 
chloride alone or where this salt composes the main alkali, 
but where much carbonate is present 700 to 1400 is more 
than the crop can withstand safely. Traphagen (29) 
places the limit for sulphates the same for oats as for 
wheat and barley. 



214 CROPS FOR ALKALI LAND 

Rye has been highly recommended as a crop to produce 
forage and green manure for alkali lands too strong for 
most ordinary crops. Hansen (5a) used it with good success 
in reclaiming land containing about 17,100 parts per mil- 
lion of alkali, mostly sodium sulphate, and was able to re- 
duce the alkali content of the soil considerably by turning 
the crop under as green, manure. The seedbed for rye 
should not contain more than about 5000 parts per million 
of white alkali, however, or a poor growth will result. 
With rye, as with other crops to be grown on alkah lands, 
the quantity of seed sown should be greater than for crops 
on ordinary land and the seedbed made as free from 
salts as possible by cultural methods and irrigation. 
Kearney (17) regards rye as being about equal to barley 
in alkali resistance, or withstanding for a successful grain 
crop between 4000 and 6000 parts per million of white 
alkali. 

Corn has been found (12, 13, 17) to fail on very weak 
alkali soils and its production on soils containing large 
quantities of alkali is not ordinarily to be recommended. 

Rice has been found to do well in Eg3^pt (17) where 
the alkali content of the soil was as high as 10,000 parts 
per million, a large part of which was sodium chloride, 
but this was under very favorable conditions. The soil 
can be kept moist or wet in growing rice so that more alkaU 
may be present without injury than where a lower soil 
moisture content is maintained. 

Emmer is usually considered to be about equal to wheat 
in its resistance to alkali. Grain crops other than the 
above mentioned have not given promise on alkali lands. 

Sunflowers were found by Loughridge (19) to endure 
3740 parts per million total salt of which 3290 parts per 
miUion were sodium sulphate. 



ROOT AND VEGETABLE CROPS 215 

Root and vegetable crops often do well on ulkuli lands, 
although some are rather sensitive and some, such as 
beets and potatoes, suffer in quality when excessive alkali 
is present. 

Sugar-beets have been found to be one of the most satis- 
factory crops grown on alkali lands in the United States. 
After they are once well started they will endure enormous 
quantities of alkaU. Trouble is sometimes experienced 
in getting a stand where the soil contains more than 2000 
to 3000 parts per million of white alkali or about 500 
parts per million of black. The quality of the roots is 
impaired for sugar-making when the alkali consists of 
sodium chloride or nitrates in appreciable quantities. In 
alkali soils, such as those of certain sections of Colorado 
and California in which nitrates form an appreciable 
quantity of salts, the beets are often over-sized and low 
in sucrose and purity of the juices. Headden (9) holds 
that ordinary alkali, essentially sulphates, are not det- 
rimental, but even comparatively small quantities of 
nitrates cause injury to the quality of the beets. 

As sugar-beets, after passing the deUcate seedling stage, 
feed rather deep in the soil the quantity of alkali that may 
be present in the surface of the beet land may be very 
great. Jensen and Strahorn (16) found beets apparently 
doing well in a soil, the top foot of which contained about 
30,000 parts per milHon of alkali, a large part of which 
was sodium chloride. During the earlier part of the season, 
these beets were barely able to withstand 15,000 parts 
per million of alkali in the upper foot even though the 
moisture content of the soil was rather high. It is fre- 
quently possible to get a stand of beets by giving the 
land a heavy irrigation to (lri\'c the alkali below, just 
before planting. After getting started beets will endure 



216 CROPS FOR ALKALI LAND 

and yield well with 4000 to 6000 parts per million of alkali, 
provided it consists mostly of the white type. With 
sodium carbonate or sodium chloride composing a con- 
siderable portion of the alkali, however, the quantity 
endured will be less. Beets will endure considerably more 
sodium carbonate than most of the other important crops 
of western United States. They have been found doing 
well on land containing from 500 to over 700 parts per 
million of this salt. Where the soil is crusted due to the 
action of sodium carbonate, however, or where it becomes 
strong about the seedlings, the stand will be imperfect and 
the yield poor. 

Sodium chloride has been found to have a deleterious 
effect on the quality of sugar-beets and where this con- 
stituent of alkali exceeds 400 to 500 parts per milHon the 
quality is likely to be inferior, although the growth may 
be excellent. Beets will endure sodium chloride in the 
soil in strengths of 2000 to 4000 parts per million, but 
they will not be fit for sugar-making when grown on such 
soils. Neither the quality nor the quantity of beets 
produced in the presence of 4000 to 6000 parts per million 
of sodium sulphate is likely to suffer after the plants 
once get a good start. 

Potatoes have not been found to do well on alkali land. 
Their quality is usually poor, especially where part of the 
salts consist of sodium chloride or nitrates. These salts 
also seem to cause the skin of the potato to be poorly 
developed so that the keeping quality of the tubers is 
impaired. Potatoes may be apparently doing well in 
the presence of as much as 2000 to 4000 parts per million, 
but they are likely to be watery and of poor keeping quaUty 
when even as much as 1000 parts per million is present. 
It is best to plant crops other than potatoes on even the 
weak alkali land. 



ROOT AND VEGETABLE CROPS 217 

Onions may be regarded as fairly tolerant of alkali, 
at least in the form of sodium carbonate and nitrates. 
They were observed (2) making a good growth in a soil 
containing 4500 to 5700 parts per million of total salts, 
a large part of which was calcium nitrate. With white 
alkali, Kearney (17) places the limit as between 4000 and 
6000 parts per million. Shutt (26) found them growing 
well in a sandy loam soil containing 1080 parts per million 
of total salts of which 530 parts per million was sodium 
carbonate in the upper six inches, the soil to a depth of 
5 feet containing 1800 parts per million total salts of which 
1350 parts per million w^as sodium carbonate. The highest 
quantity observed by Hilgard (13) was 2405 parts per 
million of total salts. 

Asparagus is said by Kearney (17) to do well in soil 
containing as high as 6000 parts per million of white alkali 
and to be benefited by sodium chloride when in small 
quantities. 

Celery will grow practically unaffected where the total 
salt in the soil does not amount to more than about 4000 
parts per million and is said to withstand sodium chloride 
very well. 

Radishes were found by Loughridge (19) to be unaffected 
by 3930 parts per million of total salts, 550 parts per mil- 
lion of sodium carbonate, or 3240 parts per million of sodium 
sulphate. 

Other vegetables have not been found to withstand alkali 
in large quantities. Sodium chloride seems particularly 
injurious to vegetables such as radishes, carrots, parsnips, 
and artichokes, the quality being very poor. The seeds 
of most of the vegetables are small and the seedlings 
delicate so that vegetable growing on alkali land is very 
hazardous. 



218 CROPS FOR ALKALI LAND 

Fiber crops are not of great importance in most alkali 
sections of the United States at present. There are, 
therefore, few data for these crops. 

Flax {Liniuni usitaiissimimi) is reported by Kearney (17) 
as having produced a good crop where the surface foot of 
soil contained 4000 parts per million of salts. "The pres- 
ence of an excessive quantity of salts in the soil below the 
first foot apparently had no injurious effect." 

Cotton is being grown in parts of the Southwest where 
considerable alkali is found. It has been produced ex- 
tensively under alkaline conditions in Egypt where it was 
found to be rather resistant to alkali. The quality of 
the cotton is impaired and the production is considerably 
reduced where the quantity of alkali is great. For the 
short-staple varieties where quaUty is not so important 
the soil may contain 4000 to 6000 parts per million without 
serious injury, according to Kearney (17). As with the 
vegetables, cotton is injured in quality more by sodium 
chloride than the other salts. Like sugar-beets, it is a 
crop which requires considerable cultivation and it shades 
the land during its maturity so that the cultural methods 
tend to keep the alkali from concentrating at the surface. 

Trees and shrubs have been studied as to alkali resist- 
ance in the United States very little except in California. 
It is so difiEicult to determine whether the death of trees 
and shrubs is due to alkali or to other unfavorable condi- 
tions that data of practical value are almost unobtainable. 
A rising water-table is one of the common conditions ac- 
companying alkali, and as the roots of trees and shrubs 
are in undrained soil which might kill the trees were no 
alkali present at all, to what extent the injury can be as- 
suredly due to alkali is a difficult question. Where the 
alkali is not evenly distributed the feeding zone of the 



TREES AND SHRUBS 219 

trees is so diflicult to determine that the resistance of trees 
is a much more uncertain matter to determine than it is 
for the smaller cultures. 

Fruit trees and shrubs which might tolerate large quanti- 
ties of alkali frequently do not gi\e satisfaction because the 
quality of the fruit is injured by certain kinds of alkaH. 
This is especially true of the more delicately flavored 
fruits, such as the peach. In case there is a very ap- 
preciable quantity of alkali in the soil it is usually better 
to grow the more resistant forage or grain crops until 
the land has been reclaimed for fruit. 

Date palms are the most resistant of fruit trees and per- 
haps the most resistant of cultivated plants. They are 
unfortunately not adapted to the alkali lands of the United 
States with the exception of certain of the southwestern 
regions. The date palm has been known to grow in the 
presence of 30,000 to 40,000 parts per million of alkali, 
largely sodium chloride. Where there are layers of soil 
containing only 6000 to 10,000 parts per million, this 
palm will produce abundant crops even where the sur- 
rounding or surface soil contains enormous quantities of 
alkali. There is no apparent injury where the soil con- 
tains no more than 5000 parts per million of the white 
alkali, although where black alkali is encountered the 
resistance is less. About 600 parts per million of sodium 
carbonate, 5000 parts per million of sodium chloride, and 
20,000 to 50,000 parts per million sodium sulphate have 
been successfully withstood. Palm groves are found 
flourishing where the upper soil contains 15,200 parts 
per million of alkali and the surface of the ground is white 
with alkali. The quality of the fruit is apparently not 
greatly impaired even where the alkali, which is about 
one-half sodium chloride, reaches a concentration of 10,000 
parts per million. 



220 CROPS FOR ALKALI LAND 

Grapes, according to the California observations, are 
the most resistant fruit which does well in many of the 
alkali sections. They were found to grow well in soil 
containing 2860 parts per million of total salts, 630 parts 
per million of sodium carbonate, 770 parts per million of 
sodium chloride, or 2550 parts per million of sodium 
sulphate. 

Olives were unaffected in a soil containing 2520 parts 
per million of total salts, 180 parts per million of sodium 
carbonate, 420 parts per million of sodium chloride, or 
1920 parts per million of sodium sulphate. 

Other fruits tolerated very small quantities of salts, so 
small that even the mildest alkali land would cause trouble. 
Orange, almond, fig, pear, and apple trees withstood be- 
tween 1000 and 2000 parts per million most of which was 
sodium sulphate, whereas the toxic limit for prune, peach, 
apricot, lemon, and mulberry trees was below 800 parts 
per milhon for this type of alkali. Hecke, De Greeff, 
and Heime (11) found that apricot, peach, and similar 
fruit trees did not suffer from gummosis when there was 
salt in the soil about the trees. This would indicate that 
small quantities of salt in the soil would be advantageous, 
but the quantity could not be large enough to be called 
alkali land without causing injury at least to the quality 
of the fruit. 

Other trees tested by California experimenters and which 
withstood over 1000 parts per million of total salts were 
Kolreuteria 4600 parts per million. Oriental sycamore 
2670 parts per million, and eucalyptus trees 2530 parts 
per million. The former two trees withstood 620 and 200 
parts per million of black alkali, respectively, and 790 
and 1270 parts per million of sodium chloride, respectively. 
Eucalyptus trees will withstand very large quantities of 



REFERENCES 221 

white alkali and up to about 400 parts per million of black 
alkali without apparent injury. Washingtonia palm and 
camphor trees were rather sensitive to alkali even in small 
quantities, especially of sodium carbonate and sodium 
chloride. 

As these trees are adapted only to the warmer sections 
with mild winters, they are of little value outside of the 
Southwest. For the other sections certain of the poplars 
or cottonwoods are probably the best adapted to alkali 
lands. Locusts are also likely to do well where the alkah 
is not too strong. 

Plants recommended by Kearney (17) as being suitable 
for hedges and windbreaks are Russian olive {Elaeagnus 
songorica) (Bernh.) (Gray, F. F. and G.) for moderate 
alkali, golden willow (probably Salix vitellina aurea) for 
regions having severe winters, pomegranate {Piinica grana- 
tum), and tamarisk {Tamarix gallica) which are de- 
cidedly resistant, for the southwestern alkali lands, as 
well as certain of the larger salt-bushes. A triplex hreivcri 
and A. longiformis are the species especially recommended 
for this purpose. 



REFERENCES 

1. COE, H. S. Sweet Clover: Growing the Crop. U. S. D. A. Farmers' 

Bui. 797 (1917), p. 13. 

2. Connor, S. D. Indiana Soils containing an Excess of Soluble Salts 

Proc. Ind. Acad. Sci. 1916, pp. 403-404. 

3. DoRSEY, C. W. Alkali Soils of the United States. U. S. D. A. Bur. 

Soils, Bui. 35 (1906), pp. 7-196. 

4. Uymond, T. S., and Houston, D. Salt Water Flood of November 

29, 1897. Jour. Essex Tech. Lab. Vol. 3, pp. 173-182. 
(Abs. E. S. R. II, pp. 326-327.) 

5. EcKART, C. F. A Consideration of the Action of Saline Irrigation 

Water. Hawaiian Sugar Planters' Sta. Rpt. 1902. 



222 CROPS FOR ALKALI LAND 

5a. Hansen, D. Crops on Alkali Land, Huntley Project, Montana. 
U. S. D. A. Bui. 135 (1Q14), iQ pp. 

6. Harris, F. S. Soil Alkali Studies. Utah Sta. Bid. 145 (igi6), pp. 3- 

21. 

7. H.VRRis, F. S., and Pittman, D. W. Relative Resistance of Various 

Crops to Alkali. Utah Sta. Bui. 168 (1919), 23 pp. 

8. Headden, W. p. Alkalis in Colorado. Colo. Sta. Bui. 239 (1918). 

58 pp. 

9. Headden, W. P. Deterioration in Quality of Sugar-beets Due to 

Nitrates Formed in the Soil. Colo. Sta. Bui. 183 (1912), 179 pp. 

10. He.\dley, F. B. The Work of the Truckee-Carson Experiment Farm 

in 1912. U. S. D. A. Bur. PI. Ind. Cir. 122 (1913), pp. 13-23. 

11. Hecke, E. van, et al. The Use of Common Salt for the Prevention 

of Gummosis of Fruit Trees. Jour. Soc. Agr. Brabant et Hainaut, 
52 (1907), No. 13, pp. 366-367. (Abs. E. S. R. 18, pp. 948-949.) 

12. HiLGARD, E. W. Salts Compatible with Ordinary Crops. Cal. Sta. 

Bui. 128 (1900), 8 pp. 

13. HiLG.ARD, E. W. Soils, pp. 466-481. (New York, 1906.) 

14. Holmes, J. G. Walla Walla District, Washington. U. S. D. A. 

Bur. Soils, Field Oper. (1902), pp. 722-723. 

15. Jensen, C. A., and Mackie, W. W. Soil Survey of the Baker City 

Area, Oregon. U. S. D. A. Bur. Soils, Field Oper. (1903), pp. 1151- 
II 70. 

16. Jensen, C. A., and Strahorn, A. T. Soil Survey of the Bear River 

Area, Utah. U. S. D. A. Bur. Soils, Field Oper. (1904), pp. 1018- 
1019. 

17. Kearney, T. H. Choice of Crops for .Alkali Land. U. S. D. A. 

Farmers' Bui. 446 (191 1), 32 pp. 

18. Kearney, T. H. Plant Life on Saline Soils. Jour. Wash. Acad. 

Sci. vol. 8, No. 5. 

19. LouGHRiDGE, R. H. Tolerance of Alkali by Various Cultures. Cal. 

Sta. Bui. 133 (1901), 42 pp. 

20. LouGHRiDGE, R. H. Tolerance of Various Crops lor Alkali. Cal. 

Sta. Rpts. 1895-96, 1896-97, p. 49. 

21. Mead, C. E. Crops for Alkali Soils. N. Mex. Sta. Bui. 33 (1900), 

PP- 37-39- 

22. Means, T. H., and Gardner. F. D. The Alkali of the Soils. U. S. 

D. A. Bur. Soils, Rpt. 64 (1899) pp. 56-57. 

23. Neill, N. p. Soil Survey of the Laramie Area, Wyoming. U. S. 

D. A. Bur. Soils, Field Oper. (1903), pp. 1092-1093. 

24. Nelson, A. Some Native Forage Plants for Alkali Soils. Wyo. 

Sta. Bui. 42 (1899), 45 pp. 

25. Sanchez, A. M. Soil Survey of Provo Area, Utah. U. S. D. A, 

Bur. Soils, Field Oper. (1903), p. 1141. 



REFERENCES 223 

26. Shutt, F. T., and Smith, K. A. The Alkali Content of Soils as Re- 

lated to Crop (Irowth. J'rans. Roy. Soc. (Canatla), Sor. Ill (1918), 
XVII. 

27. Smith, J. d. Forage I'laiils for Cultivation on .\lkali Soils. U. S. 

D. A. Yearbook (i8q8), pp. 535-550. 

28. ToTTiNGH.\M, W. K. A Preliminary Study of the Influence of Ciiloridcs 

on the Cirowth of Certain .Xgricultural Plants. Jour. Am. Soc. Agr. 
II (iqiq), pp. 1-32. 
2g. Traphaokx, F. VV. The Alkali Soils of Montana. Mont. Sta. Bui. 
54 (1904), pp. 93-121. 



CHAPTER XV 
ALKALI WATER FOR IRRIGATION 

One source of alkali trouble may be from irrigation 
water which carries in solution large quantities of soluble 
salts. Water passing over or seeping through alkah land 
gradually dissolves the soluble material which it retains 
in solution. Drainage water coming from land that is 
high in soluble salts should therefore be thoroughly ex- 
amined before being used for irrigation. 

Streams that flow through rock formations, such as the 
Mancos shale, which contain large quantities of salts are 
often so strongly impregnated that their waters are rendered 
injurious for irrigation. Springs or wells are often found 
containing sufficient soluble salts to make the use of their 
waters dangerous. A limited quantity of alkali in the water 
would not be so serious if it were not for the fact that the 
land on which it is used may already have sufficient alkali 
so that the addition of any more would make it unfit for 
crops. 

Variation in the original salt content of the soil makes 
it very difficult to determine just how much alkali can be 
present in irrigation water before it becomes dangerous. 
Notwithstanding the difficulty of giving exact figures, 
the problem is so important that it merits the most pro- 
found study. This is realized when the extensive use of 
irrigation water is known. 

About 95,000,000 acres of land, or about 7 per cent of 
the total area under cultivation in the world, is farmed 

224 



SOURCES OF CONTAMINATION 225 

by irrigation. Tliis area will be greatly enlarged in the 
future. The 25 or 30 per cent of the earth's surface which 
receives too little rainfall to allow farming without ir- 
rigation includes some of the richest known farming land. 
The southwestern parts of Africa, South America, and 
Australia; the northern part of Africa; the northern and 
western parts of North America and Asia; and parts of 
eastern, southern, and western Europe are all too dry to 
permit of successful farming without the use of more water 
than falls naturally on the land. The successful farming 
of these areas is possible only through irrigation. There 
is much more land needing irrigation than there is water 
to supply the need. For this reason, it is important to be 
able to utilize all available water. Even water that would 
not be used if sufficient pure water could be had must 
be utilized. It becomes necessary therefore to know just 
what are the danger limits of alkali in irrigation water. 
If the farming of certain lands requires irrigation with 
water that will render the land unproductive, it is highly 
desirable to prevent the erection of expensive structures 
for diverting the water and laborious operations in bring- 
ing the land into a state of cultivation. 

Som'ces of Contamination. — Much valuable informa- 
tion has been gathered in the past on the different phases 
of the alkali-irrigation-water problem. It has been ob- 
served that most of the contamination of irrigation streams 
is due to seepage and drainage waters which find their 
way back into the rivers and canals. Observations by 
the U. S. Geological Survey and the U. S. Department of 
Agriculture show that 65 per cent of the Gila River 
water (27) and 30 to 40 per cent of the Salt River water (3) 
(32) found its way back into the rivers after being used 
for irrigation. 



226 ALKALI WATER FOR IRRIGATION 

Numerous analyses of river and canal waters show the 
great quantities of soluble salts added to the streams by 
seepage water. In Colorado, a river increased in total 
salts from no parts per million to 1178 parts per million 
in traveling 20 miles (28) ; the Jordan River, Utah, in a 
course of 14 miles changed from 890 parts per million total 
salts to 1970 parts per million (11); the Sevier River, 
Utah (12), in running from Junction to Sigard, a distance 
of 60 miles, had its total salt content increased from 205 
parts per million to 831 parts per million and by the time 
it had reached Delta, 150 miles from Junction, its salt 
content had reached 13 16 parts per million; the Pecos 
River, at Roswell, New Mexico, contained 760 parts per 
million total salts, and about 30 miles below 2020 parts 
per million were found and there were corresponding in- 
creases until at a point about 150 miles below the last- 
mentioned place, the river contained over 5000 parts per 
milUon (11) (8). These rivers all illustrate the amount 
of contamination from seepage water that may occur in 
almost any river. 

At places where drainage water from strongly alkali 
soils empties into streams even greater pollution of the 
water may be expected. Water passing through a soil 
containing 20,000 parts per million of alkali in the upper 
four feet has been found to contain over 34,000 parts per 
milHon of salts when it reached the drainage outlet (5). 
Such water emptying into the bed of a small stream, as 
is frequently done during the height of the irrigation 
season, may make the further use of this water extremely 
dangerous. The water of the Arkansas River is very 
pure at Canon City, Colorado, but it is entirely diverted 
for irrigation further down. At a point about 120 miles 
below where seepage had increased the stream to consider- 



SOURCES OF CONTAMINATION 



227 



able size again, it held about 2200 ])arts per iiiillion of 
salts (15). 

Evaporation from free water surfaces is the direct cause 
of the high alkali content of certain irrigation waters. 
Lake Tulare, California, which has no outlet, was once 




Fig. 32. — The More Tender Trees are being Killed with 
Rising Alkali, while Alfalfa is Still Unaffected. 

considered a source of irrigation water. Due to evapora- 
tion its waters increased in concentration from 1400 parts 
per million in 1880 to 3500 parts per million in 1888, and 
to 5200 parts per million in 1889 (20). Irrigation water 
for the Carlsbad district. New IVIexico, is stored in a large 
reservoir or lake fed by the Pecos River. It was found 
that for several weeks in May and June, 1899, the evapora- 
tion of this water which already contained between 2000 
anrl 3000 part? per million of total salts, was equal to over 



228 ALKALI WATER FOR IRRIGATION 

200 second-feet (11). The Gila River (18) was found to 
contain 1200 parts per million of total salts on June 5. 
By June 23 it had risen to 1546 parts per million and by 
July 8 to 192 1 parts per million. 

Water from torrential rains not having time to sink into 
the ground, especially on rather impervious soils, dissolves 
the surface salts and carries them into the streams below. 
Where much alkali is concentrated in the upper soil and 
surface of the catchment basin of the rivers, the high 
flood waters may become somewhat saline. During 1899 
and 1900, studies of the Salt and Gila Rivers of Arizona 
showed them to contain more salts during flood periods, 
caused by these sudden showers, than during the low 
stages when the salt content might ordinarily be expected 
to be highest (8). Similarly, observations of the Pecos 
River showed the first flood waters to contain 5100 parts 
per million of salts, whereas later it contained only 2430 
parts per million. The Salinas River, California, affords 
another example of this type of concentration of salts (48). 
It therefore cannot be safely stated that high waters are 
best for irrigation purposes. 

Streams with their beds running through portions of an 
alkali stratum of soil may become excessively alkali. 
Salt Creek, Utah, passes over a part of the bed of old Salt 
Lake which contains large deposits of common salt. After 
doing so, its water was found to contain 2300 parts per 
million of total salts, of which 1629 parts per milhon are 
common salt. 

Observed Toxic Limits. — The exact quantity of alkali 
which renders water unsuitable for irrigation is uncertain; 
it varies with the soil, the crop, the rainfall, the amount of 
water used, the drainage conditions, and a number of other 
factors. 



OBSERVED TOXIC LIMITS 229 

Hilgard (17) (19) states that although 685 parts per mil- 
lion (40 grains per gallon) of the common alkali salts should 
be the limit under most conditions, the nature of the 
salts will modify the hmits considerably. As httle as 342 
parts per million of sodium carbonate has in some instances 
caused serious injury in three or four }ears, while as much 
as 2739 parts per million of the less toxic salts would not 
be harmful. From his work in California, Mackie (24) 
states that where the salts "are principally bicarbonate 
and chloride of sodium, irrigation v/ater containing more 
than 600 to 700 parts per million of salt should not be 
applied except to porous, well-drained soils. Guthrie (13) 
considers 500 parts per million of sodium carbonate as a 
tolerable quantity of this salt even when as much as 150 
parts per million of sodium chloride are also present. 

Where the salts are more of the sodium-sulphate type, 
larger quantities are permissible. Forbes (18) states that 
with good drainage 1000 parts per million of salts in ir- 
rigation water is an objectionable but permissible degree 
of salinity for the soils of the Salt River, Arizona. In 
the Pecos Valley (26) 2500 parts per million to 3000 parts 
per million of salts were considered the danger zone where 
about 50 per cent of the salts in the water were of sodium 
— mostly sodium chloride and sodium sulphate. Good 
drainage in the upper part of the valley makes possible 
the use of water of higher salinity than is possible in lower 
parts of valleys where the soil is heavier and likel}- to 
contain more alkali. Land, after being irrigated five 
years with water containing 3900 parts per milhon of salts, 
was abandoned because of the accumulation of alkali and 
seepage water. 

Experiments in Wyoming (31) show that where only 
small quantities of water are added, practically all of the 



230 ALKALI WATER FOR IRRIGATION 

salts in the water are retained by the soiL Large quanti- 
ties of water apphed weekly or semi-weekly kept the salts 
moving downward continually. Means (25) states that 
the Arabs in the Desert of Sahara raise good crops of dates, 
deciduous fruits, and garden vegetables when irrigated 
with water containing as high as 8000 parts per million 
of total salts, 50 per cent of which in some cases was sodium 
chloride. Such alkalinity, however, would not be per- 
missible except with very resistant crops on light, sandy, 
or well-drained soils and where great care is given to keep 
the water from evaporating and concentrating the salts 
at the surface. 

Without special attention to drainage, a California soil 
irrigated with water containing 766 parts per million 
sodium chloride, 327 parts per million sodium carbonate, 
and 315 parts per million sulphates was proving injurious 
to an orchard after three years (19). Impervious clay 
soils might be injured with water too weak in alkali to 
have any noticeable elTect on well-drained ones, because 
of the cumulative effect. 

Even in a soil with good drainage in Arizona, it was 
found that when water containing over 1000 parts per 
million of salts, two-thirds of which was sodium chloride, 
was applied, 50 to 60 per cent of the salts added in the water 
were retained by the soil or at least never appeared in the 
seepage water of the district (8). Soils flooded by sea 
water for 6 to 8 hours were found to contain 2000 parts 
per million of sodium chloride in the surface soil where un- 
fiooded land contained only 100 parts per million. How- 
ever, in a drainage experiment on the Swan Tract, Utah, 
an alkali soil containing less than 3000 parts per million 
of salts in the upper 4 feet of soil, when flooded with water 
containing about 1500 parts per million of salts yielded 



TYPICAL ALKALI WATERS 231 

drainage water containing over ii,ooo parts per million 
of salts. The applications of water were large, sometimes 
as much as i6 inches being applied at one time, which 
makes a great difference in the retention of the salts by the 
soil (5). Hawaiian experiments with water containing 
2cxx> parts per million of salts show that on a moderately 
porous soil there was very little accumulation of salt pro- 
vided occasional heavy irrigation was given (4). Wash- 
ing the salts out of the soil occasionally with the relatively 
pure winter and spring waters has proved very beneficial 
to some alkali districts. 

In semi-arid sections, the salt content of irrigation water 
may be much higher than in the arid without causing trouble 
because the amount of water necessary to supplement the 
rainfall is smaller and the larger precipitation washes the 
salts out of the soil much more readily. The U. S. Geo- 
logical Survey (32) has attempted to classify irrigation 
waters as good or bad by use of a formula based on the 
toxicity of the individual alkali salts to field crops. Such 
formulae, while instructive as to the relative injuriousness 
of the waters, are subject to criticism because the factors 
mentioned above modify the limits through a wide range. 
A formula to be of much practical value must consider 
these factors. 

Composition of Typical Alkali Waters. — To show the 
variation in the salt content of some of the principal streams 
of the West, the analyses given in Table XXII are pre- 
sented. It should be kept in mind that these results will 
not hold strictly for different seasons and different sections 
of the stream, but they are useful in gaining a general 
idea of the nature of the alkali in different streams. 



232 



ALKALI WATER FOR IRRIGATION 



Table XXII. Analyses of Some Characteristic Alkaline 
River and Lake Waters of Western United States 



(July) Salt River, Ariz 

(Oct.) Gila River, Ariz 

(Oct.) Colorado River, Ariz... . 
(June) Colorado River, Ariz. . . 
(Low water) Pima Ditch, Ariz.. . 

Buckeye Canal, Ariz 

1880, Lake Tulare, Cal 

1889, Lake Tulare, Cal 

1 89 1, Lake Elsinore, Cal 

Salinas River at San Lorenzo 

Creek, Cal 

Estrella River, Cal 

San Benito River, Cal 

Cache la Poudre, 2 mi. above 

Greeley, Col 

Platte River below Cache la 

Poudre, Colo 

Arkansas at Rocky Ford, Colo. . 
Mill Creek (cold spring), .Mont. 

Walker Lake, Nev 

Pecos River, N. M 

Arkansas River, Salt Fork, Okla. 
Cimarron, north of Kingfisher. . 

Brazo River, Texas 

Rio Grande River, Texas 

Jordan River, Utah 

Utah Lake, Utah 

Sevier River at Delta, Utah. . . 

Beaver River, Utah 

Malad River, Utah 

Salt Creek, Utah 



Percentage of Sails 



CI 



594 
36.5 
17.4 

17-5 



39-9 
17.4 
20.3 



II. 7 
154 
13.8 

2-S 

3-8 
4.9 

74 
23.8 
22.6 
51-3 
53-5 
30-9 
21.6 

35-5 
26.9 
25.0 
23-8 
50.0 
46.2 



HO4 



9.2 
14.6 
35-6 
12.5 



7-3 
16.9 

20.8 



48.6 

30-9 
29.0 

60.0 

60.7 

17-3 
21.3 

43-7 
8.6 
6.2 

25-5 
30.1 
26.5 
30.1 
24.1 

254 
2.9 
3-6 



CO3 Na 



I3-I 
12.8 



28.6 



9.6 
26.5 

19-5 



24.9 

33-5 
35-8 



7-9 

2-3 

38.3 
7-3 

8.8 
2.6 
3S-I 
17-3 
i-S 
1.2 

•7 

7-1 

"•5 

2.7 

8.5 
17.9 
12. 1 

4-7 
12.7 



40.7 
27.2 
18^2 
I3-I 



I.I 
-1-5 



^6 



16.7 i.o 
17.9 

I3-I 54 



9.8 



12.0 
14-5 
23-5 
34-6 
14.0 

36-7 
38.3 

20.8 
14.8 
26.1 
18.3 
16.4 
25-5 
374 
28.9 



4 

■3 

1.4 

trace 

.8 



1.8 



Ca Mg 



6.5 

94 

12.4 

154 



6.6 

1-5 
•3 



4-5 
6.3 
6.6 

12.3 

13.2 
12.8 

lO.I 

I.I 

134 
1.6 



13-7 
7.6 

5-3 
5-3 
2.8 



3-3 



2.9 



1.6 



SiOi 



3-5 

5 
2. 2 

3 
(a) 
7 
5 
6 

[(b) 

.6 
.8 
.6 



2.0 
3-8 



Total 
Solids 



P.P.M. 



1,391 
1,08s 
1,045 
321 
1,210 
1,972 
1,360 
4,910 
1,444 

3,689 
1,131 

1,571 

1,011 
2,134 
3,747 
2,476 

2,384 

5,962 

11,392 

1,136 

791 

892 

1,254 

1,316 

990 

4,395 
2,180 



(a) 47.9% NaCl. 

(b) 16.1% Na.COs, 69.0% NaCl, Na2S04, etc., 7.1% CaCOs, MgCOo 
and silica. 



No analyses of well waters used for irrigation are pre- 
sented because well waters have been found to vary so 
greatly even in short distances that each well must be 
tested separately. There are certain large artesian basins 



TYPICAL ALKALI WATERS 



233 



like that of the upper San Luis Valley, Colorado, the 
waters of whieh all contain larger or smaller fjuantities of 
sodium carbonate, — ^ which permit of rough classification. 
Irrigation w'ell waters seldom change in composition as 
do open streams because the water is not subject to the 
various factors causing fluctuations. 

To show the seasonal fluctuations in the salt content of 
rivers, analyses of the Salt and Gila Rivers of Arizona (8) 
are given in Tables XXIII and XXIV. These are excep- 
tional variations but illustrate how little a single analysis 
might mean. The Sevier River, Utah, show^s a somewhat 
less fluctuation because not influenced by flood waters. 
This is shown in Table XXV (33). 



Table XXIII. Seasonal Variation in Salt Content of Salt River, 
Arizona, Expressed as Parts Salt per Million of Water 



Pate 



(a) Aug. i-Sept. i, 1899.. 

(b) Sept. 2-Scpt. 9, 1899. 

(c) Sept. 10-Oct. 9, 1899. 

(d) Oct. lo-Oct. 17, 1899. 

(e) Oct. i8-T)ec. 30, 1899. 

(f) Feb. 17-May 30, 1900 

(g) June i-Aug. 4, 1900. . 



Total 

SrtLTS 



724 
IIOO 

II42 

952 

1026 
1069 

I39I 



Composition of the Waters 



Na CI SO4 CO3 Ca Mg K SiOs 



122 
183 

274 



309 
327 
407 



279 
315 
441 



409 
437 
594 



979 
481 
727 



748 
764 
919 



802 



724 



402 
437 
f)5i 



206 
III 
583 



465 
529 
355 



(a) High and low summer water. Average of four weekly composites 
of samples taken daily. 

(b) Summer flood water. One weekly composite of daily sample taken. 

(c) High and low summer waters. Average of four weekly composites 
of dailv samples. 

(d) Winter flood water. One composite of daily samples taken. 

(e) Low winter water. Average of ten weekly composites of daily 
samples. 

(f) Low winter water. Average of thirteen weekly composites of daily 
samples. 

(g) Very low summer water. Average of eight weekly composites of 
daily samples. 



234 



ALKALI WATER FOR IRRIGATION 



Table XXIV. Seasonal Variation in Salt Content of Gila River, 
Arizona, Expressed as Parts Salt per Million of Water 



Date 



(a) Nov. 28, 1899-Jan. 18, 1900 

(b) Feb. i-Mar. 7, 1900 

(c) Aug. i-Aug. 14, 1900 

(d) Aug. is-Aug. 28, 1900 

(e) Sept. i-Sept. 28, 1900 

(f) Sept. 29-Nov. 5, 1900. . . . . 



Total 
Salts 



1 1 36 
541 
925 
471 

1085 



Composition of the Waters 



Na 



CI 



401 
383 
965 



.S74 
364 



SO4 



15s 
165 
947 
130 
964 

145 



CO3 



653 
(393 



Ca 



524 
663 
686 
836 
S7I 
937 



Mg 



264 
289 
175 
IS7 
121 



178 



226 
151 



SiOa 



752 
652 



266 
5" 



(a) Low winter water. Average of seven weekly composites of samples 
taken daily. 

(b) Low winter water. x\verage of five weekly composites of samples 
taken daily. 

(c) Summer flood water. Average of two weekly composites of daily 
samples. 

(d) Summer low water. Average of two weekly composites of daily 
samples. 

(e) Summer flood water. Average of four weekly composites of daily 
samples. 

(f) Summer low water. Average of five weekly composites of daily 
samples. 



Table XXV. Seasonal Variation in Salt Content of Sevier River, 
Utah, Expressed as Parts Salt per Million of Water 



Date 


Total 
Salts 


Composition of the Waters 


Ca 


Mg 


SO^ 


K 


CI 


HCO3 


NN 


July 29 

August 12 

August 24 

September 18.... 
September 21. . . . 

October 5 

October 19 

November 9 


958 
1104 
1268 
iigo 
1426 
1406 
1436 
1376 


74 
84 
82 
92 
86 
74 
84 
84 


100 
87 
87 
79 
83 
75 
74 
74 


222 
272 
288 
256 

329 
328 

334 
326 


10 

12 
8 

10 
4 
4 

II 

ID 


58 

90 

IIS 

lOI 
221 
210 
223 
204 


278 
290 
284 
292 
264 
249 
284 
290 


1-7 
1.6 
1 . 1 
1-7 

•4 
.8 

■9 
•9 



Factors Modifying Toxic Limits of Salt. — Under or- 
dinary conditions irrigation by the flooding method with 



TOXIC. LIMITS OF SALTS 235 

saline water has been found better than by the furrow 
method. This is especially the case where such good 
drainage prevails that large quantities of water may be 
applied to leach out any accumulation of salts. Experi- 
ments have shown that land Hooded every 8 days with 
alkaH water contained less than one-third the quantity 
of alkali found in the temporary ridges under furrow ir- 
rigation and about 27 per cent of that found in unculti- 
vated tree rows. 

Hawaiian experiments (7) show that with large applica- 
tions of water containing about 3430 parts per million 
(200 grains per gallon) of common salt, large quantities 
of lime, magnesia, and potash are rendered available. 
Excessive irrigations to prevent the alkali from accumulat- 
ing at the surface washed out large quantities of lime and 
magnesia. Soils not well supplied with lime are injured 
much more by alkali than those well supplied. It was 
found in Wyoming (31) that alkali irrigation water caused 
a considerable loss of calcium sulphate and calcium car- 
bonate from the soil. Experiments in Oregon (i) show 
that calcium carbonates and nitrates wash out of the soil 
faster than supplied in the irrigation water. 

It has been found in some regions that the dissoh'ing 
action of alkali — the chloride and sulphate salts — on 
lime destroys the impervious hardpan layer often found 
a foot or two beneath the surface, thus allowing drainage 
to go on more freely. 

In the Southwest, especially in New Mexico, certain of 
the streams carry calcium sulphate in solution some of 
the time. The salt neutralizes and makes less toxic the 
sodium carbonate found at times in the soils of the district. 
If but little or no black alkali is present, as is the case in 
that of the Pecos River irrigation water may contain 



236 ALKALI WATER FOR IRRIGATION 

much larger quantities of total salts than would other- 
wise be permissible. On soils where an impenetrable 
hardpan exists, sometimes caused by sodium carbonate, 
the permissible salinity is generally lower than without 
such a condition. 

During dry years, a single irrigation with alkali water 
may mean the difference between a crop and a failure, 
provided the crop can withstand the alkali in the water. 
The limits in such cases might be much higher than in 
cases where it is necessary to irrigate frequently. On a 
clay loam soil containing a medium quantity of alkali in 
the Bear River Valley, Utah, the use of irrigation water 
containing 4395 parts per million of total salts, 3625 parts 
per million of which was sodium chloride, caused almost 
immediate wilting or death of grain. In the Carlsbad 
district, New Mexico (26), water containing 4352 parts 
per million total salts consisting of 1682 parts per mil- 
lion sodium chloride and 600 parts per million sodium 
sulphate injured young sugar-beets when freely applied. 

In Europe (37) the use of irrigation water containing 
5CC0 to 10,000 parts per million of salt caused dwarfing 
of the better grasses and legumes so that the yield was 
considerably reduced. Seedling grass was killed with 
these concentrations and even 500 to 1000 parts per mil- 
lion injured the stand. 

Corn (2) suffered during its vegetative period when 
irrigated with chloride and carbonate waters in concen- 
trations as high as 7389 parts per million, but tomatoes 
did not. Sugar cane (6) (7), when irrigated with pure 
water, yielded 11 tons more sugar per acre than when ir- 
rigated with water containing 3430 parts per million of 
salts. The density of the cane juice was lowered and the 
salt content raised by the use of the alkali water so that 



REFERENCES 237 

the purity of the juices and the quantity present was re- 
duced. In these experiments 6.75 and 8.79 acre-feet of 
water were applied during the season and occasional hea\'y 
irrigations were given to keep the salts from accumulating. 
\\ hen the quantity of water used was reduced considerably 
so that the strength of the soil solution became high such 
a large quantity of alkali proved fatal (6) (7). 

Using cofifee, cocoa, and other plants to determine the 
concentration of water that may be used with safety (22), 
it was found that the limits were between 5000 and 15,000 
parts per million although the result were somewhat 
complicated by rainfall. 

From a survey of a number of localities along the 
Potomac River, Scofield (30) assumes that the salt water 
limit for wild rice is about 1754 parts per million (0.03 
normal) for sodium chloride. The growth was just about 
proportionate to the strength of the solution when less 
than this amount was present. 

Water to be used in irrigating rice should never contain 
more than 3000 parts per million of salt, according to 
Fraps (9) of Texas. 

Harris and Butt (14), after a rather extensive study of 
the use of alkali water for irrigation, concluded that under 
average conditions more than 500 parts per milhon of 
sodium carbonate, 1000 parts per million of sodium chlo- 
ride, 4000 parts per million of sodium sulphate, and 4000 
parts per million of the ordinary mixture of salts are 
dangerous. In case there were no drainage from the land, 
lower limits than those mentioned would have to be used. 

REFERENCES 

I. AiLEN, R. W. Work of the Umatilla Reclamation Project Experi- 
ment Farm in 1Q15 and 1916. U. S. D. A. Bur. PI. Ind., W. 1. A. 
Circ. 17, p. 17. 



238 ALKALI WATER . FOR IRRIGATION 

2. BoRDiGA, O. Irrigation Experiments with Brackish Water. Intm. 

Inst. Agr. (Rome), Mo. Kul. Agr. Intel, and Plant Dis. 4 (1913), 
No. 8. (Abs. E. S. R. 30, p. 886.) 

3. Code, W. W. Irrigation in the Salt River X'allcy (Arizona). U. S. 

D. A., O. E. S. Bui. 104 (1902), p. 555. 

4. Crawley, J. T. Water-holding Power and Irrigation of Hawaiian 

Soils. The Application of Nitrate of Soda; the Accumulation of 
Salt in Hawaiian Soils. Hawaiian Planters' Mo. 21 (1902), No. 8, 
pp. 358- ,363- (Abs. E. S. R. 14, p. 555.) 

5. DoRSEY, D. W. AlkaU Soils of the United States. U. S. D. A. Bur. 

of Soils, Bui. 35 (1906), 196 pp. 

6. EcKART, C. F. Recent Experiments with Saline Irrigation. Hawaiian 

Sugar Planters' Sta. Bui. n, p. 14. (Abs. E. S. R. 16, p. 650.) 

7. EcKART, C. F. A Consideration of the Action of Saline Irrigation 

Water. Hawaiian Sugar Planters' Sta. Rpt. (1902), pp. 24-74, 
76-100; Rpt. (1903), pp. 37-41. 

8. Forbes, R. H. The River Irrigating Waters of Arizona — Their 

Character and Effects. Ariz. Sta. Bui. 44 (1902), pp. 145-214. 

9. Fraps, G. S., The Effect of Salt Water on Rice. Tex. Sta. Bui. 

122 (1909), 6 pp. 

10. FuLAYKOV, N., and Kossovich, P. The Soils of the Muganj Steppe 

and Their Transformation into Alkali Lands by Irrigation. Ann. 
Inst. Agron. (Moscow), 12 (1906), pp. 27-255. (Abs. E. S. R. 18, 
p. 818.) 

11. Gardner, F. D. A Soil Survey in Salt Lake Valley, Utah. U. S. 

D. A. Bur. of Soils, Rpt. 64, pp. 77-114. 

12. Greaves, J. E., and Hirst, C. T. Composition of the Irrigation 

Waters of Utah. Utah. Sta. Bui. 163 (1918), 43 pp. 

13. Guthrie, F. B. Water on the Farm. New South Wales, Dept. 

Agr. Farmers' Bui. 121, 42 pp. (1918). 

14. Harris, F. S., and Butt, N. I. The Use of Alkali Water for Irriga- 

tion. Utah Sta. Bui. 169 (1919). 

15. Headden, W. P. A Soil Study, IV. The Ground Water. Colo. 

Sta. Bui. 72 (1902), 47 pp. 

16. Headden, W. P. The Waters of the Rio Grande. Colo. Sta. Bui. 

230 (1917), pp. 3-62. 

17. HiLGARD, E. W. The Quality of Irrigation Water in the Great Valley, 

California. Cal. Sta. Rpt. 1890, pp. 4-56. 

18. HiLGARD, E. W. Quality of Irrigation Water, pp. 246-251. (Soils, 

New York, 1906.) 

19. HiLGARD, E. W. The Use of Saline and Alkali Waters in Irrigation. 

Cal. Sta. Rpt. 1897-98, pp. 99-117. 

20. HiLGARD, E. W. The Lakes of the San Joaquin Valley. Cal. Sta. 

Bui. 82 (1889), 4 pp. 



REFERENCES 239 

21. Jenson, C. a., and Strahorn, A. T. Soil Survey of the Bear River 

Area, Utah. U. S. D. A. Bur. of Soils, Field ()[)er. (1904), pp. 995- 
1020. 

22. Ki ijri;i<, J. KlTectsuf Usiii^; Salt Sokilioiis for Walcriiit; and S|)riii- 

kling Plants. Dept. Landb. SuriiianiL- iiul. 2.S (1912), i)p. 25-31. 
(Abs. !•:. S. R. 29, p. 218.) 

23. LipriNCOTT, J. B. Storaf^e of Water on Gila River, Arizona. U. S. 

(leol. Survey, Water Supply Paper S3> P- 24. 

24. Mackie, W. W. Reclamation of White Ash Lands .\fTected with 

Alkali at Fresno, California. U. S. D. A. Bur. of Soils, Bui. 42 

(1907), P- 32. 

25. ^Ie.\ns, T. H. The Use of Alkaline and Saline Waters for Irrigation. 

U. S. D. A. Bur. of Soils, Cir. 10 (1903), 4 pp. 

26. Means, T. H., and Gardner, F. D. A Soil Survey of the Pecos Valley, 

New Mexico. U. S. D. A. Bur. of Soils, Rpt. 64, pp. 36-76. 

27. Newell, F. H. Stream Measurements for 1898. U. S. (ieol. Survey, 

.\nn. Rpt. 1899-1900, Pt. IV, pp. 343-347. 

28. O'Brine, D. Alkali vSoils of Colorado. Colo. Sta. Bui. 9 (1889), 

pp. 22-23. 

29. Otto, R. The I'lffect of Salt Water on Plants. Ztschr. Pflanzenkrank, 

14 (1904), No. 3, pp. i36-'i4o. (.Vbs. E. S. R. 16, 951.) 

30. Scofield, C. S. The Salt Water Limits of Wild Rice. U. S. I). .\. 

Bur. PI. Ind. Bui. 72 (1905), pp. 9-14. 

31. Slosson, E. E. Water Analyses. Wyo. Sta. Bui. 24 (1895), pp. 99- 

141. 

32. Stabler, H. Irrigation Waters. U. S. Geo. Survey, Water Supply 

Paper 274, pp. 177-181. 
^;i. Stewart, Robert, and Hirst, C. T. The Alkali Content of Irriga- 
tion W'ater. Utah Sta. Bui. 147 (1916), p. 13. 

34. Van Winkle, W., and Eaton, F. M. Quality of the Surface Waters 

of California. U. S. Geol. Survey, Water Supply Paper 237. 

35. Widtsoe, J. A. Irrigation Practice, pp. 77, 84. (New York, 1914.) 

36. WiLLCOCKS, W. The Nile in 1904, p. 63. (London and New York, 

1904.) 

37. Wohltman, F. The Effect of Salt Water on Cultivated Plants. 

Fuhling's Landw. Ztg. 45 (1896), No. 15, pp. 155-159. (.\bs. 
E. S. R. 7, p. 680.) 



CHAPTER XVI 
JUDGING ALKALI LAND 

A KNOWLEDGE of the physical phases of alkali is not 
sufficient; the economic questions in connection with it 
must also be given consideration. Alkali has no special 
practical interest except in its relation to the soil, which 
it may render entirely worthless if present in certain forms 
and in sufficient concentration. In its less injurious forms 
and at low concentrations it may reduce the value of the 
land but slightly. It is important, therefore, to be able 
to judge the extent of reduction in value of land due to the 
presence of alkali. Many tracts have been settled, and, 
after the expenditure of large sums of money, abandoned. 
This loss might have been saved had a proper examina- 
tion of the soil been made. 

Geology of Region. — In regions free from alkali no 
particular attention need be given to it in judging land, 
but in regions where alkali is known to exist, it must be 
kept constantly in mind by prospective purchasers of land. 
Since practically all of the arid parts of the world have 
more or less alkah, the ability to judge alkali land is very 
important. One of the first steps is to look into the origin 
of the soil to see if it came from geological formations 
that are high in soluble salts. Soils derived from sand- 
stones and shales of certain formations are practically 
always so highly charged with salts that crop production 
is difficult until the salts are leached out. A soil coming 
from a formation of this kind, even though it has a salt 

240 



GEOLOGY OF REGION 



241 



content similar to that of a soil from a limestone forma- 
tion, should be regarded with greater suspicion than the 
latter soil because of the possible recontamination from 








i^ 



Fig. ^s- — ''^ Layer of Alkali Sevi i ' i ; i s : i ^w im: 
Surface. The Possibility of such a Layer Makes an 
Analysis of the Soil Necessary before it can be 
Properly Judged. 

the unlimited supply of salt in the country rock. A knowl- 
edge of the geology of a region, therefore, is a valuable 
supplement to other information in judging alkali land. 



242 JUDGING ALKALI LAND 

General Appearance. — One who is familiar with alkali 
can tell a great deal by the general appearances of the land. 
The presence of surface accumulations of salts, the nature 
of the crust, the general condition and kind of vegetation, 
the appearance of the subsoil in cuts and excavations, the 
slope of the surface, the soil texture and structure, and 
numerous other general appearances are helpful in judging 
alkali conditions. These superficial observations, however, 
must not be relied on completely. For example, a soil 
having a high gypsum content and being free from the 
highly soluble salts may, through constant evaporation 
of water at the surface, cause the soil to be covered com- 
pletely with white powdery crystals which would seem to 
indicate a serious alkali condition. Land of this character 
could easily be undervalued since the gypsum is not suf- 
ficiently soluble to cause injury to vegetation and its 
presence might not be undesirable. 

On the other hand, a soil may show very little surface 
indication of alkali; it may contain a good growth of certain 
kinds of vegetation; yet an analysis might show that at 
some distance below the surface there is a layer of soil 
that is highly charged with salts. This land would only 
need to be brought under cultivation and irrigated to make 
the subsoil alkali a real source of danger. Appearances 
are helpful, but alone they are not sufficient. 

Native Vegetation. — As already discussed in con- 
siderable detail in Chapter VI, the native vegetation is 
one of the most valuable indicators of the presence of 
dangerous quantities of alkali. It is probably the best 
single means of judging alkali land. Certain plants 
such as sagebrush {Artemesia tridcntata) do not live in 
the presence of high concentrations of salts and where 
these plants are found growing vigorously the land may 



ANALYSIS OF THE SOIL 243 

he considered to be conii)arati\'ely free from alkali. Certain 
other i)lants such as salt f^rass (Distichlis spicala) are sel- 
dom found except on land hi<^d-ily charged with sail, and 
where found the soil should be thoroughl}- investigated 
before an attempt is made to use it for agriculture. Since 
this question has already been so fully discussed, no de- 
tails will be given here. Chapter VI should be consulted 
for further information. 

The Water-table. — Alkali lands are often wet. Sur- 
face accumulations of salt usually result from a rapid 
evaporation of water which rises from a water-table that 
is comparatively near the surface. There are soils high 
in alkali with a water-table hundreds of feet below the 
surface. In these soils the ground w^ater has nothing to 
do with the alkali accumulation. Soils are frequently 
found containing a medium quantity of salt distributed 
through considerable depth. With the introduction of 
irrigation and a consequent raising of the water-table to 
within a few feet of the surface, an ideal condition is pro- 
\'ided for a concentration of these diffused salts at the 
surface. This may render entirely unproductive a soil 
that previously raised good crops. A thorough knowledge 
of ground-water conditions is, therefore, important be- 
fore a person is able to make an intelligent judgment re- 
garding alkali land. 

Analysis of the Soil. — It is impossible to get an adequate 
idea of alkali land without having a chemical analysis of 
its water-soluble material. As has already been explained, 
a superficial examination may be somewhat deceiving, 
and it is necessary to know the nature and concentration 
of the salts to considerable depth before being able to tell 
definitely how the soil will act and whether or not the alkali 
is likely to cause trouble. The depth to which the soil 



244 JUDGING ALKALI LAND 

should be analyzed depends on a number of factors. Four 
and 6 feet are often taken as standards but lo feet is 
better. At least an occasional sample should be taken to 
this depth to see that in the deep subsoil there is not a 
layer of high concentration that will cause trouble later. 

The exact determinations to be made will depend on 
the thoroughness of the investigation desired. A complete 
chemical analysis of all the water-soluble material would 
be desirable, but a fair idea can be had with much less 
work. An absolutely necessary determination to any sort 
of intelligent diagnosis would include total soluble salts, 
chlorides, carbonates, and sulphates. In comparatively 
few regions where nitrates are high, they should also be 
determined. Where any large part of the sulphates are 
calcium sulphate, calcium should be determined in order 
that the calcium sulphate may be subtracted from the total 
soluble salts and the sulphates. Calcium sulphate is not 
sufficiently soluble in the soil solution to be toxic to vege- 
tation, but where comparatively large quantities of water 
are used in extracting the soil for analysis, considerable 
calcium sulphate is contained in the solution, and where it 
forms any large part of the dissolved material it should be 
taken into consideration. It is also desirable to have 
determinations made of other bases such as magnesium 
and sodium, but these determinations are not so valuable 
as the others that have been mentioned. 

The methods of analysis, particularly the method of 
making extractions, must be taken into consideration in 
interpreting the results. Different methods give different 
results; consequently the methods should always be known. 
Details of the various methods are given in Chapter VII. 

Possibility of Reclamation. — The value of alkali land 
is affected very materially by the possibility and the ex- 



ECONOMIC FACTORS 245 

pcnsc of reclaiming it. Some alkali lands are so situated 
that reclamation is practically impossible or would be 
so expensive as to be prohibitive. Very flat land that 
does not have an outlet for drainage is difficult to reclaim. 
Land that is so heavy that drainage water percolates 
slowly has its salts washed out with difficulty. Some lands 
have a good slope and the soil has a texture suitable for 
drainage, but there is no available supply of water to aid 
in the process of reclamation; hence, drainage is useless. 
It is apparent, therefore, that not only the quality of the 
soil itself must be taken into account, but also the condi- 
tions associated with its reclamation. 

Economic Factors. — Physical features of the soil must 
be used in connection with a number of economic factors 
in judging an alkali soil. The soil has no particular value 
aside from the economic returns it will yield. These 
depend not alone on actual crop yields, but also on cost 
of production, market conditions, and a number of other 
factors. Distance from market and from suitable farm 
help may make it unprofitable to cultivate even a fertile 
soil, much less a soil the productivity of which is decreased 
by any unfavorable condition such as the presence of alkali. 
Climatic conditions may not be such as to make possible 
the raising of profitable crops that are resistant to alkali. 
A soil of a given alkali content might be suitable for agri- 
culture in a region where date palms could be produced 
at a profit and yet be entirely worthless for the crops of 
the temperate zone. It is evident, therefore, that alkali 
soil of any particular type or composition cannot be said 
to be suitable for agriculture without taking into con- 
sideration numerous conditions other than those associated 
with its merely physical features. 

The demand for an increased acreage of land to supply 



246 JUDGING ALKALI LAND 

food for the world will make it necessary to use more and 
more the lands that were previously not considered 
worthy of cultivation. This will demand that greater 
attention be given to alkali lands, and that more intelligence 
be put into understanding and reclaiming them. 



INDEX 



Absorption of: 

salts by soils, 109 

water, 34 
Abyssinian highland, source of soil, 

II 
Acid, sulphuric, beneficial, 116 
Action, mass, 106 
Advantages of drainage, 167 
Afghanistan, alkali in, 13 
Africa, alkali in, 10 
Alberta, alkali in, 7, 8 
Aldajem, R., 28, 32 
Alexandria, rainfall of, 11 
Alfalfa, 197 
Algeria, alkali in, 10 
Ali, B., 103, 134, 139 
Alkali: 

black, formation of, 108 

-heath, as alkali indicator, 63, 

69 
-indicating plants, descri|jtion 

of, 74 
-loving plants, 63 
meadow-grass, 206 
meadow-grass, as alkali indi- 
cator, 64 
movement, rate of, 148 
-resistant crops in reclamation, 

162 
salts, antagonism between, 113 
waters, composition of, 231, 232 
water for irrigation, 224 
Almond, 220 
America, alkali in, 6 



American cowslip, as alkali indicator, 
64 

Ames, J. \V., 14 

Ammonification, efTect of salts, 138 

Analysis : 

by biological method, 103 
by freezing-point method, 102 
of Egj-ptian soil, 12 
of soil in judging land, 243 

Analytical methods, comparison of, 

8S 

Analytical process, 90 

Antagonism, 105 

between alkali salts, 113, 138 
noted in soil bacteria work, 116 

Ancient seas as source of salts, 22 

Appearance in judging land, 242 

Apple, 220 

Apricot, 220 

Arabia, alkali in, 13 

Area affected with alkali, 4 

Argentina, alkali in, 10 

Aridity necessary for alkali, 6 

Arizona, alkali in, 8 

Arizona method of alkali analysis, 

84, Si- 
Arrow: 

grass, as alkali indicator, 64 
weed, as alkali indicator, 63, 73 

Asia, alkali in, 13 

Asparagus, 217 

Aster, as alkali indicator, 64 

Atroplex, as alkali indicator, O3, 70 

Atti, R., 14 

Australia, alkali in, 14 

Australian salt-bush, 207 



247 



248 



INDEX 



B 

Bacterial activities increased by 
drainage, 169 

Baluchistan, alkali in, 13 

Bancroft, R. L., 14, 57, 58 

Barley, 212 

Barnes, J. H., 103, 134, 139 

Barnyard grass, 208 

Bases, determination of, 92 

Bates, P. H., 190, 191 

Beam, W., 102, 103 

Becker, A., 120, 131 

Beeson, J. L., 149, 151 

Bemmeln, J. M. von, 121, 130 

Bicarbonates, determination of, 86 

Biological: 

activity, toxic limits for, 135 
conditions and alkali, 132 
inactivity and soil sterility, 133 
method of analysis, 103 

Birdsfoot clover, 200 

Black alkali: 

formation of, 108 
neutralizing, 160 

Bluegrass, 203 

Blue-stem grass, 206 

Bombay Presidency, alkali in, 13 

Borates, effect on capillarity, 128 

Bordign, O., 238 

Bouyoucos, G. J., 102, 103 

Breazeale, J. F., 29, 32, 40, 50. 54, 
58, 59, 117, 130, 160, 166 

Brazil, alkali in, 10 

Bridge method, 94 

Briggs, L. J., 80, 128, 129, 130, 131, 

144, 151 
British Columbia, alkali in, 7 
Brome grass, 202 
Brown, C. F., i66, 174, 190 
Brown, P. E., 15, 103, 136, 138, I39 
Bryan, H., 104 

Bud-brush, as alkali indicator, 64 
Buffum, B. C, 45, 51, 54, 58 



Bulrush, 208 

as alkali indicator, 64 

Burd, J. S., 14 

Bureau of Soils publications, 9 

Bureau of Standards work on ce- 
ment, 176 

Burgess, P. S., 118, 139 

Burke, E., 174, 190 

Bushy samphir, as alkali indicator, 
63, 66 

Butt, N. I., 151, 237 

Buttercup, as alkali indicator, 64 



Cairo, rainfall of, no 
Calcium : 

carbonate hardpan, 124 

chloride, solubility, 105 

determination of, 92 

effect on salts, 116 

sulphate antagonistic with so- 
dium sulphate, 115 

sulphate, solubility, 105 
Caldwell, J. S., 116, 117 
California: 

alkali in, 8, 9 

method of alkali analysis, 84, 85 

sodium sulphate experiments, 
108 
Cameron, F. K., 20, 22, 28, 32, 44, 
46, 104, 113, 118, 124, 131, 

ISO. 151 

Camphor tree, 221 

Canada, alkali in, 7 

Canadian soils, 114 

Canal lining, 32 

Capillarity affected by alkali, 128 

Carbonates: 

determination of, 86 
effect on capillarity, 128 
source of, 28 

Carrying capacity of drains, 180 

Carter, E. G., 136, 139 



INDEX 



249 



Catlin, C. N., 104 
Cause of hardpan, 123 
Celery, 217 
Cell: 

effect of alkali on, 35 

sap concentration, 35 
Cement drain tile, 174 
Changing soil structure, 119 
Chemical: 

equilibrium, 105 

methods of determining alkali, 81 

treatments for alkali, 161 
Chezy-Kutter formula, 179 
Chili, soluble salt deposits in, 10 
Chloride: 

determination, 88 

effect on capillarity, 130 
Clarke, F. W., 14, 18, 20, 32 
Clovers, 200 
Code, W. W., 238 
Coe, H. S., 199, 221 
Colloids, effect of alkali on, 122 
Colorado, alkali in, 8, 9 
Comparison of analytical methods, 

Composition of: 

alkali in judging land, 243 

alkali waters, 231, 232 

earth's crust, 18 

hardpan, 127 

lithosphere, 17 

ocean water, 18 

rocks, 16, 17 

soil-forming minerals, 17 
Conner, S. D., 221 
Construction methods, 183 
Contamination: 

source of, 154 

of irrigation water, 225 
Copper, effect on salts, 116 
Corn, 214 

Cost of drainage, 189 
Cotton, 218 



Cottonwood, 221 
Coupin, H., 46, 48, 58 
Cowslip, as alkali indicator, 64 
Crawley, J. T., 238 
Crepis, as alkali indicator, 64 
Cressa, as alkidi indicator, 63, 70 
Cretacious deposits, 23 
Crimson clover, 200 
Cropping in reclamation, 162 
Crops for alkali land, 192 
Crust, effect on evaporation, 157 
Cultivation to reduce evajjoration, 
154 

D 

Dakota formation, 23, 24 

Date palms, 219 

Davis, R. O. E., 104, 121, 128, 131 

Davy, J. B., 60, 80 

Deakin, A., 14 

Decomposition of rocks, 19 

Deflocculation of soil by alkali, 121 

De Greef, H., 220 

Demoussy, E., 118 

Description of alkali-indicating 

plants, 74 
Desolation, caused by alkali, 3 
Determination of: 

alkali, 81 

bases, 92 

bicarbonatcs, 86 

calcium, 92 

carbonates, 86 

chloride, 88 

magnesium, 93 

nitrate, 89 

sodium, 93 

sulphiUe, 89 

total solids, 86 
Determining need of drainage, 170 
Dieckman, G. P., 176, 190 
Dimo, N. A., 15, 146, 151 
Dissolved matter washed to sea, 19 



250 



INDEX 



Distribution of alkali, 6 

Dorscy, C. W., 20, 32, 147, 148, 151, 

i66, 221, 238 
Drain outlets, 188 
Drainage: 

advantages of, 167, 169 

cost of, 189 

for reclamation 162, 167 

machines, 186, 187 
Drains: 

carrying capacity of, iSo 

size of, 178 

types of, 171 
Duggar, B. M., 40 
Dwarf samphir, as alkali indicator, 

63,66 
Dymond, T. S., 213, 221 
Dynamite in breaking hardpan, 123 



Earth's crust, composition of, 18 
Eaton, F. M., 239 
Eckart, C. F., 221, 23S 
Economic factor in: 
crop choice, 195 
judging land, 243 
Efifect of: 

alkali on: 

ammonification, 13S 
bacteria, 132 
capillarity, 128 
colloids, 122 
germination, 36 
nitrogen fixation, 137 
plant structure, 38 
soil tilth, 120 
surface tension, 128 
salts on: 

evaporation, 13c 
moisture movement; 128 
soil organisms on sterility, 133 
water-table, 145 
Egypt, alkali in, 10, tt 



Egyptian: 

clover, 200 

millet, 208 
Electric bridge method, 94 
Emmer, 214 
English rye grass, 204 
Equilibrium : 

chemical, 105 

in soil solution, iii 
EucaljT^tus, 220 
Europe, alkali in, 13 
Evaporation : 

of moisture, 130 

of saline lakes, 27 

reduction of, 155 
Experiments: 

in loam, 53 

in sand, 49 

with rice, 114 

with sodium sulphate in Calif., 
108 
Extract of soil, 81 



Factors affecting resistance, 192 

Failyer, G. H., 82, 104 

False golden rod, as alkali indicator. 

73 
Fescue, 204 
Fiber crops, 218 
Field peas, 200 
Flax, 218 
Flocculation of soil, effect of alkali, 

121 
Flooding to reclaim land in Egyi)t, 

160 
Forage crops, 197 
Forbes, R. H., 229, 238 
Formation of: 

black alkali, loS 

carbonates, 28 

hardpan, 123 

nitrates, 30 



INDEX 



251 



Formation of: 

sodium bicarbonate, io6 
Formula for Mass Action, 106 
Fowler, T. W., 134, 139 
Fraps, G. S., 237, 238 
Freak, G. A., 102, 103 
Free, E. E., 121, 131 
Freezing-point method of anal} sia. 

102 
Fruit trees, 219 
Fulaykov, N., 23S 
Fungi in soil and fertility, 133 


Gandcchon, II., 152 
Gardner, F. D., 123, 124, 131, 197, 

238 
Gedroits, K.. K., 22, 29, 32, 131 
Geographical distribution of alkali, 6 
Geology in judging land, 240 
Gericke, W. F., 115, 118, 
Germination: 

effect of alkali on, 36 

experiments, 44 
Giant r>'e-grass, 207 
Gila River water, 225 
Glaux, as alkali indicator, 64 
Golden willow, 221 
Goldthorpe, H. C, 136, 139 
Grade of drain, 177 
Goosefoot, as alkali indicator, 64 
Grain crops, 210 
Grapes, 220 
Grasses, 2co 

Greasewood, as alkali indicator, 63, 6S 
Great Basin, alkali in, 8 
Greaves, J. E., 22, 33, 91, 103, 104, 

136, 138, 139, 238 
Green River formation, 27 
Gutlirie, F. B., 55, 56, 58, 229, 23S 
Gypsum: 

for black alkali, 160 

leaching of, 129 



H 

Hall, A. D., 120, 131 

Hansen, D., 142, 151, 222 

Hansteen, B,, 48, 58, 117 

Hardpan, 122 

Hare, R. F., 84, 104, 150, 151 

Harris, F. S., 32, 40, 53, 58, 118, 130, 

131, 151, 152, 158, 166, 203, 

222, 237 
Hart, R. A., 1C5, 166, 174, 179, 189, 

190 
llarter, L. L., 38, 40, 59 
Haselhoff, E., 48, 54, 58 
Headden,\V. P., 32, 57, 142, 145, 146, 

152, 161, 166, 176, 190, 211, 

215, 222, 238 
Headley, F. B., 222 
Hebert, A., 15 
llecke, E., 220, 222 
Ileime, C, 220 
Hcileman, W. H., 127, 131 
Helms, R., 55, 56, 5S 
Hicks, G. H., 40, 46, 58 
Ililgard, E. W., 9, 15, 32, 40, 69, So, 

121, 123, 131, 144, 147, 152, 

158, 160, 166, 197, 207, 217, 

222, 229, 238 
Hill, E. G., IS 
Hills, T. L., 137, 139 
Hirst, C. T., 91, 104, 238, 239 
Ilissink, D. J., 152 
Hitchcock, E. B., 136, 139 
Holmes, J. G., 212, 222 
Houston, D., 213, 221 
Hungary', alkali in, 13 



Imperial Valley, alkali in, 8 
Inactivity of organisms and soil 

steriUty, 133 
India, alkali in, 13 
Indicating plants, description of, 74 
Indicator value of vegetation, 60 



252 



INDEX 



Injury, nature of, 34 

Inkweed, as alkali indicator, 63, 65 

Irrigation: 

systems in Egypt, 12 

water, 224 

water, carrier of alkali, 30 

water, composition of, 231, 232 

water, toxic limits, 22S 

weed, as alkali indicator, 63, 73 

Isham, R. M., 3a, 33 

Italian r>'e grass, 204 

Italy, alkali in, 13 

J 

Japanese wheat grass, 203 

Jcffery, J. A., 190 

Jensen, C. A., 80, 211, 212, 215, 222, 

239 
Joffa, M. B., 118 
Johnson, D. R., 138, 139 
Jost, L., 40 

Judging alkali land, 240 
Jurassic deposits, 23 



Kearney, T. H., 15, 39, 40, 44, 46, 
47, 58, 59, 80, 113, 118, 197, 
199, 200, 201, 202, 203, 204 
205, 208, 210, 212, 213, 214, 
217, 218, 221, 222 
Kcllerman, K. F., 122, 131 
Kclley, W. P., 29, 32, 118, 135, 137, 

139 

Kern greasewood, as alkali indi- 
cator, 63, 66 

King, F. H., 82, 146, 152, 190 

Klein, M. A., 139 , 

Knight, W. C, 32, 118 

Knop's solution, 43 

Kochia, as alkali indicator, 63, 72 

Kolotov, G. I., 152 

Kolreuteria, 220 



Kossovich, P., 59, 144, 152, 238 
Kravkov, S., 152 
Kuiiper, J., 239 



Lakes, saline, 27 

Land : 

judging, 240 

method of reclaiming, 154 

Lapman, M. H., 128, 129, 144, 151 

Law of Mass Action, 106 

Laying out system, 177 

Leaching of gypsum, 129 

Leather, J. W., 14, 15 

Leaves to reduce evaporation, 157 

Le Clerc, J. A., 43, 50, 54, 59, 117 

Legumes, 200 

Lemon, 220 

Lcsage, P., 59 

Lime, corrective for magnesium, 114 

Limestone, composition of, 17 

Lining of canals, 32 

Limit of biological activity, 335 

Limits, toxic, 42 

Linsley, J. D,, 166 

Lipman, C. B., 103, 115, 118, 134, 
13s, 137, 139, 161, 166 

Lippincott, J. B., 239 

Lithosphere, composition of, 17 

Little rabbit brush, as alkali indica- 
tor, 63, 73 

Loam, experiments in, 53 

Loughbridge, R. H., 121, 131, 147, 
152, 160, 166, 200, 201, 203, 
204, 206, 208, 209, 211, 212, 
214, 217, 222 

Lumber drains, 180, 184 

M 
Mackie, W. W., 80, 142, 145, 147, 

152, 212, 229, 239 
MacOwan, P., 15 



INDEX 



253 



Magnesium: 

determination of, 93 

chloride, solubility, 105 

corrected by lime, 114 

sulphate, solubility, 105 
Magowan, Florence N., 44, 59 
Mancos shale, 24, 25, 26, 27 
Manhole for drain, 189 
Mann, H. H., 15 
Marchal, E., 48, 59, 140 
Marquenne, L., 118 
Marsh grass, as alkali indicator, 64 
Masoni, G., 121, 131 
Mass Action, 106 

McCool, M. M., 102, 103, 142, 152 
McLane, J. W., 80 
Mead, C. E., 222 
Meade, R. K., 175, 190 
Meadow fescue, 204 
Meaning of alkali, 5 
Means, T. H., 12,15, i>^) 22, 33, 160, 

166, 197, 239 
Merrill, G. P., 18 
Mesopotamia, alkali in, 13 
Method: 

electric bridge, 94 

of reclaiming alkali land, 154 
Methods: 

comparison of, 85 

of constructing drains, 183 

of determining alkali, 81 
Micheels, H., 40, 45, 59 
Microorganisms, effect of alkali on, 

132 
Miller, C. E., 142, 152 
Millets, 208 
Minerals: 

alkali in, 19 

in rocks, 16 
Miyake, K., 59, 114, 118 
Montana: 

alkali in, 9 

formation, 25 



Montana: 

method of alkali analysis, 84, 85 
Moisture: 

evaporation, 130 

movements, 128 
Modiola, 206 
Morocco, alkali in, 10 
Mousetail, as alkali indicator, 6 
Movement of: 

alkali with water, 142 

moisture, 128 

salt, rate of, 148 

soluble salts, 141 

various salts, 146 
Mulch to reduce evaporation, 154 
Mulberr>', 220 
Munter, E., 138 
Muntz, A., 152 
Myers, H. C., 80 



N 
Native: 

grasses, 205 

vegetation as alkali indicator, 
60,63 

vegetation in judging land, 242 
Nature of alkali injury, 34 
Need of drainage, 170 
Neill, N. P., 199, 201, 222 
Nelson, A., 208, 222 
Neutralizing sodium carbonate, 160 
Newell, F. H., 239 
Nile River Valley, alkali in, 11, 12 
Nitrate: 

determination, 89 

formation, 30 
Nitrates, eflect on capillarity, 129 
Nitric acid for alkali land, 161 
Nitrogen fixation, effect of salts on, 

137 
North America, alkali in, 6 
Nutrient solutions, 43 



254 



INDEX 



O 

Oat-grass, 204 
Oats, 213 
O'Brien, D., 239 
Ocean: 

as source of alkali, 21 

water, 18 
Olives, 220 
Onions, 217 
Open drain, 172 
Orange, 220 
Orchard: 

grass, 202 

killed by alkali, 39 
Organisms and soil fertility, 132 
Origin of: 

alkali, 16 

hardpan, 123 
Osterhout, W. J. V., 117, iiS 
Otto, R., 239 

Oudh Province, alkali in, 13 
Outlets, 188 



Plasmolysis of cell, 35 
Plowing under alkali, 158 
Plowmans' wort, as alkali indicator, 

,64 
Pomegranate, 221 
Poplars, 221 
Poncelet's formula, 178 
Port Said, rainfall of, 11 
Potatoes, 216 
Practical drainage, 167 
Prairie grass, 206 
Precipitation records, 11 
Preliminary survey, 1 76 
Preparing solution of soil, 81 
Prevention of water absorption, 34 
Proso millet, 208 
Prune, 220 

Puchner, II., 144, 152 
Punjab, alkali in, 13 
Purple top: 

as alkali indicator, 63 

grass, 206 
Px-rrocoma, as alkali indicator, 64 



Pagnoul, A., 149, 152 

Parson, J. L., igo 

Patten, H. E., 150, 151, 152 

Peach, 220 

Pear, 220 

Peas, 200 

Peimersel, R. L., 80 

Pepper grass, as alkali indicator, 64 

Persia, alkali in, 13 

Peterson, Wm., 22, 30, 33 

Pfeffer, W., 36, 41 

Phillips, A. J., 190, 191 

Phosphates, effect on capillarity, 12S 

Physical condition of scil, 119 

Pigweed, as alkali indicator, 64 

Pinckney, R. ]\I., 174, 190 

Pittman, D. W., 53, 104, 203, 222 

Plant descriptions, 74 

Plants as indicators of alkali, 60, 63 



Quantity of salts to reduce yields, 56 

R 

Rabbitt brush, as alkali indicator, 

63, 73 
Radishes, 217 
Rape, 209 

Rate of alkali movement, 14S 
Reclamation: 

by cropping, 162 

methods, 154 

system in Egj'pt, 12 
Red clover, 200 
Red top, 203 

Reduced jdelds from salts, 56 
Reducing evaporation, 155 
Reh commission, 13, 14 
Reh lands, 13 



INDEX 



255 



Relation of: 

alkali to biological conditions, 
132 

alkali to physical conditions, 
119 
Removing salts from surface, 159 
Resistance : 

factors afJecting, 192 

tables, 96 
Resistant crops in reclamation, 162 
Revicl, 59 

Rhodesia, alkali in, 10 
Rice, 214 

experiment with, 114 
Robinson, J. S., 130, 131, 151, 158, 

166 
Rock, composition of, 16 
Rolct, A., 160, 166 
Root: 

crops, 215 

zone increased by drainage, 169 
Roots injured by alkali, 34 
Rushes, 20S 

Rush, as alkali indicator, 64 
Russian olive, 221 
Rye, 214 

grass, 204 



Sachsse, R., 120, 131 

Sackett, W. G., 30, ;^^, 140 

Sage brush as indicator of land, 242 

Sahara, soib of, 10 

Saline lakes, 27 

Salt: 

bushes, 207 

bush as alkali indicator, 63, 70 

crvjst, relation to evaporation, 

157 
grass, 205 
grass, as alkali indicator, 63, 73, 

243 
movement with water, 142 



Salt: 

River water, 225 

wort, as alkali indicator, 63. 

Salts: 

absorption by soils, 109 
antagonism between, 113 
by bridge method, 94 
by freezing-point method, 102 
effected by calcium, copper, 

zinc, 116 
effect of, on moisture move- 
ment, 128 
from ancient seas, 22 
in hardpan, 127 
in natural soil, 141 
movement of, 14, 146 
plowing under of, 158 
quantity to reduce yields, 56 
removal from surface, 159 
removed in drainage, 163, 164 
soluble in water, 105 
solubility of, 106 

Samphire, as alkali indicator, 63 

Sanchez, A. M., 198, 222 

Sand, experiments in, 49 

Sandsten, E. P., 166 

Sandstone, composition of, 16, 18 

Saskatchewan, alkali in, 7 

San Joaquin Valley, alkali in, 8 

Schreiner, O., 82, 104 

Scofield, C. S., 239 

Sedger, 208 

Seed germination experiments, 44 

Shading to reduce e\'aporation, 157, 
158 

Shadscale, as alkali indicator, 63, 70 

Shale, composition of, 16, 17 

Shantz, H. L., 80 

Sharp, L.T., 115, 118, 131, 137, 148, 

149. 153 
Shaw, G. W., 15 
Shinn, C. H., 152, 160, 166 
Shooting star, as alkali indicator, 64 



256 



INDEX 



Shrubs, 218, 219 

Shutt, F. T., 8, 15, 54, 59, 118, 204, 

206, 211, 212, 217, 223 
Sigmond, A., von, 15, 45, 59 
Silt basins, 188 
Sims, C. E., 90, 176 
Size of drains, 178, 181, 182 
Skinner, W. W., 104 
Slossom, E. C, 32, 40, 45, 51, 59, 

239 
Smith, E. A., 15, 206, 211, 223 
Smith, J. G., 222 
Snow, F. J., 15 
Sodium: 

determination of, 93 
bicarbonate, formation of, 106 
carbonate: 

hardpan, 127 
neutralizing of, 160 
solubility, 105 
chloride, solubility, 105 
nitrate, solubility, 105 
sulphate, experiments in Cali- 
fornia, 108 
sulphate, solubility, 105 
Soil: 

analysis of, 12 

bacteria, antagonistic results 

with, 116 
composition in judging land, 

243 
extract, 81 

fertility and organisms, 132 
indicated by plants, 60 
movement of alkali through, 141 
organisms and fertility, 132 
physical condition of, 119 
solution, equilibrium in, iii 
solution, preparation of, 81 
solution, variance in concentra- 
tion, 112 
warmed by drainage, 169 
sterility and organisms, 133 



Soils: 

absorption of salts, 109 

Canadian, 114 
Solids, determination of, 86 
Soluble : 

salt movement with water, 142 

salts, movement of, 141 

salts by bridge, 94 

salts in hardpan, 127 
Solubility: 

affected by temperature, 105, 
109, 112 

of salts, 105, 106 
Solution: 

experiments, 44 

Knop's, 43 

nutrient, 43 

preparation of, 81 
Solutions: 

alkali, 44 

nutrient, 43 

toxicity of, 43 
Sorghums, 208 
Source of: 

alkali determines methods, 154 

contamination, 154 
Sources of water contamination, 225 
South Africa, alkali in, 10 
South America, alkali in, 10 
Spike weed, as alkali indicator, 63, 

73 
Stabler, H., 239 

Strahorn, A. T., 80, 211, 215, 239 
Steik, K., 176, 190 
Stevenson, W. H., 15 
Stewart, J., 51, 123, 124 
Stewart, R., 22, 30, S3, io4, 239 
Straw to reduce evaporation, 157 
Structure of: 

plants affected by alkali, 38 

soil, 119 
Sugar-beets, 215 
Sulphate determination, 89 



INDEX 



257 



Sulphuric acid: 

beneficial, ii6 

treatment for alkali, i6i 
Sunflowers, 214 
Surface: 

removal of salts from, 159 

tension affected by alkali, 
128 
Survey for drains, 1 76 
Swan tract, reclamation of, 162 
Sweet clover, 199 
Sycamore, 220 
Symmonds, R. S., 161, 166 
Szik lands, 13 



Table of solubility of salts, 105 
Tables of electrical resistance, 96 
Tall meadow oat-grass, 204 
Tamarisk, 221 
Tamhane, V. A., 15 
Taylor, C. S., 133, 140 
Temperature, effect on salt solu- 
bility, 105, 109, 112 
Tertiary formation, 26, 27 
Texas method of alkali analysis, 84, 

85 
Tilth of soil, effect of alkali on, 120 
Timothy, 202 
Tolerance of various crops to alkali, 

196 
Torpedo drain, 173 
Total solids, determination of, 86 
Tottingham, W. E., 44, 59, 222 
Toxicity of: 

salts alone, 43 

solutions, 43 
Toxic limits: 

for bacteria, 135 

of alkali, 42 
Trailing buttercup, as alkali indi- 
cator, 64 
Transpiration reduced by salts, 34 



Traphagen, F. W., 15, 22, 33, 202, 

212, 213, 222 
Treatment of alkali affected by 

origin, 31 
Treatments for alkali, chemical, 161 
Trees, 218 
Treitz, P., 29, ^^ 
True, R. H., 41, 48, 59 
Tuber bulrush, 64 
Tulaykov, N., 15, 143, 153 
Tunis, alkali in, 10 
Turkestan, alkali in, 13 
Tussock grass, 206 

as alkali indicator, 63, 65 
Types of drains, 171 

U 

United States, alkali in, 8 
Usar lands, 13, 14 
Utah: 

alkali in, 8 

method of alkali analysis, 84, 85 



Valeria, as alkali indicator, 64 
Van Winkle, W., 239 
Vapor tension reduced by salts, 130 
Variance of soil solution concentra- 
tion, 112 
Variation in composition of water, 

234 
Vegetables, 215 

Vegetation as alkali indicator, 60, 63 
Vetch, 200 
Vinson, A. E., 104 
Vissotski, G., 15 
Vreis, H. de, 36, 44 

W 

Waggaman, W. H., 152 
Warington, R., 146, 148, 153 
Washington, alkali in, 9 
Washingtonia palm, 221 



258 



INDEX 



Water: 

absorption, prevention of, 34 

composition of, 231, 232 

for irrigation, 224 

from Gila River, 225 

from Salt River, 225 

from various rivers, 226, 227, 
228 

supply increased by drainage, 
169 

-table, effect of, 145 

-table, effect of on evaporation, 
158 _ 

-table in judging land, 243 

toxic limits, 228 
Weed, H. H., 22 
Weir, W. W., 166, 188, 191 
Western wheat grass, 203 



Wheat, 210 

White sage, as alkali indicator, 63, 72 

Whitney, M., 18, 22, 33 

Widtsoe, J. A., 239 

Wig, R. J., 190, 191 

Wild grasses, 205 

Wiley, H. W., 104 

Willcocks, W., 15, 191, 239 

Wohltman, F., 239 

Wyoming, alkali in, 8 



Yields reduced by salts, 56 
Yohe, H. S., 191 



Zinc, effect on salts, 116 



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